Human genetic variation

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to the Bantu speakers of South Africa (the Venda and Xhosa) and corresponds to the distribution of the Niger-Kordofanian language family, possibly reflecting the spread of Bantu-speaking populations from near the Nigerian/Cameroon highlands across eastern and southern Africa within the past 5000 to 3000 years (26,27). Another inferred cluster includes the Pygmy and SAK populations (green), with a noncontiguous geographic distribution in central and southeastern Africa, consistent with the STRUCTURE (Fig. 3) and phylogenetic analyses (Fig. 1). Another geographically contiguous cluster extends across northern Africa (blue) into Mali (the Dogon), Ethiopia, and northern Kenya. With the exception of the Dogon, these populations speak an Afroasiatic language. Chadic-speaking and Nilo-Saharan–speaking populations from Nigeria, Cameroon, and central Chad, as well as several Nilo-Saharan–speaking populations from southern Sudan, constitute another cluster (red). Nilo-Saharan and Cushitic speakers from the Sudan, Kenya, and Tanzania, as well as some of the Bantu speakers from Kenya, Tanzania, and Rwanda (Hutu/Tutsi), constitute another cluster (purple), reflecting linguistic evidence for gene flow among these populations over the past ~5000 years (28,29). Finally, the Hadza are the sole constituents of a sixth cluster (yellow), consistent with their distinctive genetic structure identified by PCA and STRUCTURE.

633: 925:) as a way of measuring genetic differences between populations. This statistic is often used in taxonomy to compare differences between any two given populations by measuring the genetic differences among and between populations for individual genes, or for many genes simultaneously. It is often stated that the fixation index for humans is about 0.15. This translates to an estimated 85% of the variation measured in the overall human population is found within individuals of the same population, and about 15% of the variation occurs between populations. These estimates imply that any two individuals from different populations may be more similar to each other than either is to a member of their own group. "The shared evolutionary history of living humans has resulted in a high relatedness among all living people, as indicated for example by the very low fixation index (F 982:, with much of the diversity that existed in Africa not being carried out of Africa by the emigrating groups. Under this scenario, human populations do not have equal amounts of local variability, but rather diminished amounts of diversity the further from Africa any population lives. Long and Kittles find that rather than 85% of human genetic diversity existing in all human populations, about 100% of human diversity exists in a single African population, whereas only about 70% of human genetic diversity exists in a population derived from New Guinea. Long and Kittles argued that this still produces a global human population that is genetically homogeneous compared to other mammalian populations. 829: 782: 621: 1056: 51: 902:

aspects of gene expression including chromatin states, translation, and protein levels. A study published in 2007 found that 25% of genes showed different levels of gene expression between populations of European and Asian descent. The primary cause of this difference in gene expression was thought to be SNPs in gene regulatory regions of DNA. Another study published in 2007 found that approximately 83% of genes were expressed at different levels among individuals and about 17% between populations of European and African descent.

1260: 1424:'s group makes a similar claim: "The structure of human populations is relevant in various epidemiological contexts. As a result of variation in frequencies of both genetic and nongenetic risk factors, rates of disease and of such phenotypes as adverse drug response vary across populations. Further, information about a patient's population of origin might provide health care practitioners with information about risk when direct causes of disease are unknown." However, in 2018 3639:

somewhat more probable that our early progenitors lived on the African continent than elsewhere. But it is useless to speculate on this subject, for an ape nearly as large as a man, namely the Dryopithecus of Lartet, which was closely allied to the anthropomorphous Hylobates, existed in Europe during the Upper Miocene period; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale.

8753: 40: 774: 269:, which sequenced one thousand individuals from 26 human populations, found that "a typical genome differs from the reference human genome at 4.1 million to 5.0 million sites … affecting 20 million bases of sequence"; the latter figure corresponds to 0.6% of total number of base pairs. Nearly all (>99.9%) of these sites are small differences, either single nucleotide polymorphisms or brief insertions or deletions ( 1402: 1048: 1097:(AIMs) nevertheless can be used to reliably situate many individuals within broad, geographically based groupings. For example, computer analyses of hundreds of polymorphic loci sampled in globally distributed populations have revealed the existence of genetic clustering that roughly is associated with groups that historically have occupied large continental and subcontinental regions (Rosenberg 886:. Approximately 10% of the variance in skin color occurs within groups, and ~90% occurs between groups (Relethford 2002). This distribution of skin color and its geographic patterning – with people whose ancestors lived predominantly near the equator having darker skin than those with ancestors who lived predominantly in higher latitudes – indicate that this attribute has been under strong 289: 8064: 871:. Genetic diversity decreases smoothly with migratory distance from that region, which many scientists believe to be the origin of modern humans, and that decrease is mirrored by a decrease in phenotypic variation. Skull measurements are an example of a physical attribute whose within-population variation decreases with distance from Africa. 511:, populations, varieties, or forms of organisms that exhibit gradual phenotypic and/or genetic differences over a geographical area, typically as a result of environmental heterogeneity. In the scientific study of human genetic variation, a gene cline can be rigorously defined and subjected to quantitative metrics. 841:. Populations with a greater distance between them are more dissimilar (as measured by the Fst statistic) than those which are geographically close to one another. The horizontal axis of both charts is geographic distance as measured along likely routes of human migration. (Chart from Kanitz et al. 2018) 3838:

We incorporated geographic data into a Bayesian clustering analysis, assuming no admixture (TESS software) (25) and distinguished six clusters within continental Africa (Fig. 5A). The most geographically widespread cluster (orange) extends from far Western Africa (the Mandinka) through central Africa

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Genetic data can be used to infer population structure and assign individuals to groups that often correspond with their self-identified geographical ancestry. Jorde and Wooding (2004) argued that "Analysis of many loci now yields reasonably accurate estimates of genetic similarity among individuals,

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A copy-number variation (CNV) is a difference in the genome due to deleting or duplicating large regions of DNA on some chromosome. It is estimated that 0.4% of the genomes of unrelated humans differ with respect to copy number. When copy number variation is included, human-to-human genetic variation

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In each great region of the world the living mammals are closely related to the extinct species of the same region. It is, therefore, probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; and as these two species are now man's nearest allies, it is

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Racial categories are also undermined by findings that genetic variants which are limited to one region tend to be rare within that region, variants that are common within a region tend to be shared across the globe, and most differences between individuals, whether they come from the same region or

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had 84.7 million SNPs among them. SNPs are the most common type of sequence variation, estimated in 1998 to account for 90% of all sequence variants. Other sequence variations are single base exchanges, deletions and insertions. SNPs occur on average about every 100 to 300 bases and so are the major

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populations than between them. Despite this, modern genetic studies have found substantial average genetic differences across human populations in traits such as skin colour, bodily dimensions, lactose and starch digestion, high altitude adaptions, drug response, taste receptors, and predisposition

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Comparatively speaking, humans are a genetically homogeneous species. Although a small number of genetic variants are found more frequently in certain geographic regions or in people with ancestry from those regions, this variation accounts for a small portion (~15%) of human genome variability. The

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According to a 2000 study of Y-chromosome sequence variation, human Y-chromosomes trace ancestry to Africa, and the descendants of the derived lineage left Africa and eventually were replaced by archaic human Y-chromosomes in Eurasia. The study also shows that a minority of contemporary populations

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2002). Other observers disagree, saying that the same data undercut traditional notions of racial groups (King and Motulsky 2002; Calafell 2003; Tishkoff and Kidd 2004). They point out, for example, that major populations considered races or subgroups within races do not necessarily form their own

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In a study published in 2013, Jeffrey Wall from University of California studied whole sequence-genome data and found higher rates of introgression in Asians compared to Europeans. Hammer et al. tested the hypothesis that contemporary African genomes have signatures of gene flow with archaic human

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The distribution of genetic variants within and among human populations are impossible to describe succinctly because of the difficulty of defining a "population," the clinal nature of variation, and heterogeneity across the genome (Long and Kittles 2003). In general, however, an average of 85% of

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are the descendants of the most ancestral patrilineages of anatomically modern humans that left Africa 35,000 to 89,000 years ago. Other evidence supporting the theory is that variations in skull measurements decrease with distance from Africa at the same rate as the decrease in genetic diversity.

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2000). However, in none of these cases has allelic variation in a susceptibility gene been shown to account for a significant fraction of the difference in disease prevalence among groups, and the role of genetic factors in generating these differences remains uncertain (Mountain and Risch 2004).

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Furthermore, because human genetic variation is clinal, many individuals affiliate with two or more continental groups. Thus, the genetically based "biogeographical ancestry" assigned to any given person generally will be broadly distributed and will be accompanied by sizable uncertainties (Pfaff

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theory the human population in Africa is paraphyletic to all other human groups because it represents the ancestral group from which all non-African populations derive, but more than that, non-African groups only derive from a small non-representative sample of this African population. This means

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than do populations outside Africa, partly because of the larger size of human populations in Africa over the course of human history and partly because the number of modern humans who left Africa to colonize the rest of the world appears to have been relatively low. In contrast, populations that

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exhibit 2.5-fold greater DNA sequence diversity compared to humans. These rates differ depending on what macromolecules are being analyzed. Chimpanzees have more genetic variance than humans when examining nuclear DNA, but humans have more genetic variance when examining at the level of proteins.

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Admixture mapping is a technique used to study how genetic variants cause differences in disease rates between population. Recent admixture populations that trace their ancestry to multiple continents are well suited for identifying genes for traits and diseases that differ in prevalence between

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Gene flow between two populations reduces the average genetic distance between the populations, only totally isolated human populations experience no gene flow and most populations have continuous gene flow with other neighboring populations which create the clinal distribution observed for most

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The study of human genetic variation has evolutionary significance and medical applications. It can help scientists reconstruct and understand patterns of past human migration. In medicine, study of human genetic variation may be important because some disease-causing alleles occur more often in

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An analysis of phenotypic and genetic variation including skin color and socio-economic status was carried out in the population of Cape Verde which has a well documented history of contact between Europeans and Africans. The studies showed that pattern of admixture in this population has been

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New data on human genetic variation has reignited the debate about a possible biological basis for categorization of humans into races. Most of the controversy surrounds the question of how to interpret the genetic data and whether conclusions based on it are sound. Some researchers argue that

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to human populations in their 2003 paper "Human Genetic Diversity and the Nonexistence of Biological Races". They find that the figure of 85% is misleading because it implies that all human populations contain on average 85% of all genetic diversity. They argue the underlying statistical model

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Understanding how genetic diversity in the human population impacts various levels of gene expression is an active area of research. While earlier studies focused on the relationship between DNA variation and RNA expression, more recent efforts are characterizing the genetic control of various

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populations), or geographical (hemoglobinopathies among people with ancestors who lived in malarial regions). To the extent that ancestry corresponds with racial or ethnic groups or subgroups, the incidence of monogenic diseases can differ between groups categorized by race or ethnicity, and

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may shape the human genome much more slowly than previously thought, with factors such as migration within and among continents more heavily influencing the distribution of genetic variations. A similar study published in 2010 found strong genome-wide evidence for selection due to changes in

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In many parts of the world, groups have mixed in such a way that many individuals have relatively recent ancestors from widely separated regions. Although genetic analyses of large numbers of loci can produce estimates of the percentage of a person's ancestors coming from various continental

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populations of West Africa derive between 2% and 19% of their genome from an as-yet unidentified archaic hominin population that likely diverged before the split of modern humans and the ancestors of Neanderthals and Denisovans, potentially making these groups the most archaic-admixed human

1020:– a previously unknown hominin which is more closely related to Neanderthals than to Sapiens. It was possibly introduced during the early migration of the ancestors of Melanesians into Southeast Asia. This history of interaction suggests that Denisovans once ranged widely over eastern Asia. 800:

occurs when founder populations bring only a subset of the genetic variation from their ancestral population. Second, as founders become more geographically separated, the probability that two individuals from different founder populations will mate becomes smaller. The effect of this

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can assess the ancestry of skeletal remains by analyzing skeletal morphology as well as using genetic and chemical markers, when possible. While these assessments are never certain, the accuracy of skeletal morphology analyses in determining true ancestry has been estimated at 90%.

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loci taken from 1484 individuals in 78 human populations. The upper graph illustrates that as populations are further from East Africa, they have declining genetic diversity as measured in average number of microsatellite repeats at each of the loci. The bottom chart illustrates

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The lack of discontinuities in genetic distances between human populations, absence of discrete branches in the human species, and striking homogeneity of human beings globally, imply that there is no scientific basis for inferring races or subspecies in humans, and for most

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In May 2023, scientists reported, based on genetic studies, a more complicated pathway of human evolution than previously understood. According to the studies, humans evolved from different places and times in Africa, instead of from a single location and period of time.

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Because of the common ancestry of all humans, only a small number of variants have large differences in frequency between populations. However, some rare variants in the world's human population are much more frequent in at least one population (more than 5%).

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may confer an adaptive advantage to individuals in a specific environment if an allele provides a competitive advantage. Alleles under selection are likely to occur only in those geographic regions where they confer an advantage. A second important process is

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Apart from mutations, many genes that may have aided humans in ancient times plague humans today. For example, it is suspected that genes that allow humans to more efficiently process food are those that make people susceptible to obesity and diabetes today.

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1996; Keita and Kittles 1997). For example, ~90% of the variation in human head shapes occurs within continental groups, and ~10% separates groups, with a greater variability of head shape among individuals with recent African ancestors (Relethford 2002).

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parental populations. African-American populations have been the focus of numerous population genetic and admixture mapping studies, including studies of complex genetic traits such as white cell count, body-mass index, prostate cancer and renal disease.

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Even with common diseases involving numerous genetic variants and environmental factors, investigators point to evidence suggesting the involvement of differentially distributed alleles with small to moderate effects. Frequently cited examples include

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rather than populations. Clustering of individuals is correlated with geographic origin or ancestry." However, identification by geographic origin may quickly break down when considering historical ancestry shared between individuals back in time.

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viruses to grab on and bind into. Therefore, the mutation on CCR5 gene decreases the chance of an individual's risk with AIDS. The mutation in CCR5 is also quite common in certain areas, with more than 14% of the population carry the mutation in

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Some commentators have argued that these patterns of variation provide a biological justification for the use of traditional racial categories. They argue that the continental clusterings correspond roughly with the division of human beings into

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It is commonly assumed that early humans left Africa, and thus must have passed through a population bottleneck before their African-Eurasian divergence around 100,000 years ago (ca. 3,000 generations). The rapid expansion of a previously

195:– from the overall populations where they originated; when these migrants settle new areas, their descendant population typically differs from their population of origin: different genes predominate and it is less genetically diverse. 3030: 206:

and past small population size (increasing the likelihood of genetic drift) may have had an important influence in neutral differences between populations. The second main cause of genetic variation is due to the high degree of

99:. In 2015, the typical difference between an individual's genome and the reference genome was estimated at 20 million base pairs (or 0.6% of the total). As of 2017, there were a total of 324 million known variants from sequenced 1290:

sex-biased (involving mostly matings between European men and African women) and there is a significant interaction between socioeconomic status and skin color, independent of ancestry. Another study shows an increased risk of

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ancestors and found evidence of archaic admixture in the genomes of some African groups, suggesting that modest amounts of gene flow were widespread throughout time and space during the evolution of anatomically modern humans.

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incorrectly assumes equal and independent histories of variation for each large human population. A more realistic approach is to understand that some human groups are parental to other groups and that these groups represent

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Wohns, Anthony Wilder; Wong, Yan; Jeffery, Ben; Akbari, Ali; Mallick, Swapan; Pinhasi, Ron; Patterson, Nick; Reich, David; Kelleher, Jerome; McVean, Gil (15 April 2021). "A unified genealogy of modern and ancient genomes".

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A 2009 genetic clustering study, which genotyped 1327 polymorphic markers in various African populations, identified six ancestral clusters. The clustering corresponded closely with ethnicity, culture and language. A 2018

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Limborska SA, Balanovsky OP, Balanovskaya EV, Slominsky PA, Schadrina MI, Livshits LA, et al. (2002). "Analysis of CCR5Delta32 geographic distribution and its correlation with some climatic and geographic factors".

1316:, and they may contribute to differences in the incidence of some common diseases. For the monogenic diseases, the frequency of causative alleles usually correlates best with ancestry, whether familial (for example, 6882:

Gabriel SB, Schaffner SF, Nguyen H, Moore JM, Roy J, Blumenstiel B, Higgins J, DeFelice M, Lochner A, Faggart M, Liu-Cordero SN, Rotimi C, Adeyemo A, Cooper R, Ward R, Lander ES, Daly MJ, Altshuler D (June 2002).

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after 70,000 years ago. Dispersal within Africa occurred significantly earlier, at least 130,000 years ago. The "out of Africa" theory originates in the 19th century, as a tentative suggestion in Charles Darwin's

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values between continental groups of humans (or races) of as low as 0.1 (or possibly lower) have been found in some studies, suggesting more moderate levels of genetic variation. Graves (1996) has countered that

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is more often found in people with ancestry from certain sub-Saharan African, south European, Arabian, and Indian populations, due to the evolutionary pressure from mosquitos carrying malaria in these regions.

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in 103 genes. This corresponds to 0.5% of coding SNPs. They occur due to segmental duplication in the genome. These SNPs result in loss of protein, yet all these SNP alleles are common and are not purified in

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Xue, Cheng; Raveendran, Muthuswamy; Harris, R. Alan; Fawcett, Gloria L.; Liu, Xiaoming; White, Simon; Dahdouli, Mahmoud; Deiros, David Rio; Below, Jennifer E.; Salerno, William; Cox, Laura (1 December 2016).

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have undergone dramatic size reductions or rapid expansions in the past and populations formed by the mixture of previously separate ancestral groups can have unusually high levels of linkage disequilibrium

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and affect how genes get read. The tags, "called epigenetic markings, act as switches that control how genes can be read." At some alleles, the epigenetic state of the DNA, and associated phenotype, can be

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showing average admixture of five North American ethnic groups. Individuals that self-identify with each group can be found at many locations on the map, but on average groups tend to cluster differently.

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that all non-African groups are more closely related to each other and to some African groups (probably east Africans) than they are to others, and further that the migration out of Africa represented a

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took place and that a small but significant portion, around 2–4%, of Neanderthal admixture is present in the DNA of modern Eurasians and Oceanians, and nearly absent in sub-Saharan African populations.

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genetic variation exists within local populations, ~7% is between local populations within the same continent, and ~8% of variation occurs between large groups living on different continents. The

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2004), these estimates may assume a false distinctiveness of the parental populations, since human groups have exchanged mates from local to continental scales throughout history (Cavalli-Sforza

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Wall, Jeffrey D.; Yang, Melinda A.; Jay, Flora; Kim, Sung K.; Durand, Eric Y.; Stevison, Laurie S.; Gignoux, Christopher; Woerner, August; Hammer, Michael F.; Slatkin, Montgomery (May 2013).

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because of increased fluctuations in neutral polymorphisms. Second, new polymorphisms that arose in one group were less likely to be transmitted to other groups as gene flow was restricted.

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theory for humans would predict that in Africa there exists a great deal more diversity than elsewhere and that diversity should decrease the further from Africa a population is sampled.

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1994; Hoerder 2002). Even with large numbers of markers, information for estimating admixture proportions of individuals or groups is limited, and estimates typically will have wide

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of genome-wide data was capable of recovering previously-known targets for positive selection (without prior definition of populations) as well as a number of new candidate genes.

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According to the 1000 Genomes Project, a typical human has 2,100 to 2,500 structural variations, which include approximately 1,000 large deletions, 160 copy-number variants, 915

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Some other variations on the other hand are beneficial to human, as they prevent certain diseases and increase the chance to adapt to the environment. For example, mutation in

191:(that is, they do not appear to have any positive or negative selective effect on the organism). Finally, small migrant populations have statistical differences – called the 958:

should not be used as a marker of subspecies status, as the statistic is used to measure the degree of differentiation between populations, although see also Wright (1978).

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Ramachandran S, Tang H, Gutenkunst RN, Bustamante CD (2010). "Genetics and Genomics of Human Population Structure". In Speicher MR, Antonarakis SE, Motulsky AG (eds.).

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Human Genome Diversity Panel samples was published in 2009. The study of 53 populations taken from the HapMap and CEPH data (1138 unrelated individuals) suggested that

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Pratas D, Hosseini M, Silva R, Pinho A, Ferreira P (20–23 June 2017). "Visualization of Distinct DNA Regions of the Modern Human Relatively to a Neanderthal Genome".

485:, which is the amount of variation seen in a particular population. The variability of a trait is how much that trait tends to vary in response to environmental and 306:(SNP) is a difference in a single nucleotide between members of one species that occurs in at least 1% of the population. The 2,504 individuals characterized by the 1420:

has proposed that self-identified race/ethnic group could be a valid means of categorization in the US for public health and policy considerations. A 2002 paper by

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A visual map with the regions with high genomic variation of the modern-human reference assembly relatively to a Neanderthal of 50k has been built by Pratas et al.

3912:"Study Offers New Twist in How the First Humans Evolved – A new genetic analysis of 290 people suggests that humans emerged at various times and places in Africa" 1059:

Individuals mostly have genetic variants which are found in multiple regions of the world. Based on data from "A unified genealogy of modern and ancient genomes".

211:. A small, but significant number of genes appear to have undergone recent natural selection, and these selective pressures are sometimes specific to one region. 1428:

released a study arguing against genetically essentialist ideas of health disparities between populations stating environmental variants are a more likely cause

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has the most human genetic diversity and the same has been shown to hold true for phenotypic variation in skull form. Phenotype is connected to genotype through

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Underhill PA, Shen P, Lin AA, Jin L, Passarino G, Yang WH, et al. (November 2000). "Y chromosome sequence variation and the history of human populations".

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The expansion of humans from Africa affected the distribution of genetic variation in two other ways. First, smaller (founder) populations experience greater

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Zietkiewicz E, Yotova V, Gehl D, Wambach T, Arrieta I, Batzer M, Cole DE, Hechtman P, Kaplan F, Modiano D, Moisan JP, Michalski R, Labuda D (November 2003).

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ecoregion, diet, and subsistence particularly in connection with polar ecoregions, with foraging, and with a diet rich in roots and tubers. In a 2016 study,

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is the average proportion of nucleotides that differ between two individuals. As of 2004, the human nucleotide diversity was estimated to be 0.1% to 0.4% of

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Kaessmann H, Heissig F, von Haeseler A, Pääbo S (May 1999). "DNA sequence variation in a non-coding region of low recombination on the human X chromosome".

5975:"Human leukocyte antigen profiles of Latin American populations: differential admixture and its potential impact on hematopoietic stem cell transplantation" 8834: 1512: 2010: 8013: 9317: 4268:

Manica, Andrea, William Amos, François Balloux, and Tsunehiko Hanihara. "The Effect of Ancient Population Bottlenecks on Human Phenotypic Variation".

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genetic variation. When gene flow takes place between well-differentiated genetic populations the result is referred to as "genetic admixture".

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Rosenberg NA, Pritchard JK, Weber JL, Cann HM, Kidd KK, Zhivotovsky LA, Feldman MW (December 2002). "Genetic structure of human populations".

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study of the world's populations observed similar clusters among the populations in Africa. At K=9, distinct ancestral components defined the

8791: 3921: 674:, but remained speculative until the 1980s when it was supported by the study of present-day mitochondrial DNA, combined with evidence from 933:, who affirmed these ratios, thus concluded neither "race" nor "subspecies" were appropriate or useful ways to describe human populations. 9117: 7516:"Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa" 7349:

Kaessmann H, Wiebe V, Weiss G, Pääbo S (February 2001). "Great ape DNA sequences reveal a reduced diversity and an expansion in humans".

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of 0.15–0.25 represented great variation. However, about 5% of human variation occurs between populations within continents, therefore

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Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, Dixon C, Sajantila A, Jackson IJ, Birch-Machin MA, Rees JL (April 2000).

9635: 9528: 8518: 8304: 5916:"The admixture structure and genetic variation of the archipelago of Cape Verde and its implications for admixture mapping studies" 6802:

Foster MW, Sharp RR (October 2004). "Beyond race: towards a whole-genome perspective on human populations and genetic variation".

383:, account for much more human genetic variation than single nucleotide diversity. This was concluded in 2007 from analysis of the 8455: 8201: 8006: 6171:

Tishkoff SA, Verrelli BC (2003). "Patterns of human genetic diversity: implications for human evolutionary history and disease".

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is estimated to be at least 0.5% (99.5% similarity). Copy number variations are inherited but can also arise during development.

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Ingman M, Kaessmann H, Pääbo S, Gyllensten U (December 2000). "Mitochondrial genome variation and the origin of modern humans".

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Thus, Melanesians emerge as one of the most archaic-admixed populations, having Denisovan/Neanderthal-related admixture of ~8%.

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Jorde LB, Watkins WS, Kere J, Nyman D, Eriksson AW (2000). "Gene mapping in isolated populations: new roles for old friends?".

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Cavalli-Sforza LL, Feldman MW (March 2003). "The application of molecular genetic approaches to the study of human evolution".

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The distribution of many physical traits resembles the distribution of genetic variation within and between human populations (

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Lewontin RC (1972). "The Apportionment of Human Diversity". In Theodosius Dobzhansky, Max K. Hecht, William C. Steere (eds.).

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Auton A, Brooks LD, Durbin RM, Garrison EP, Kang HM, Korbel JO, et al. (1000 Genomes Project Consortium) (October 2015).

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Human genetic diversity decreases in native populations with migratory distance from Africa, and this is thought to be due to

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Bamshad M, Wooding S, Salisbury BA, Stephens JC (August 2004). "Deconstructing the relationship between genetics and race".

3111: 8701: 8513: 8271: 8211: 5637:"Detecting Genomic Signatures of Natural Selection with Principal Component Analysis: Application to the 1000 Genomes Data" 5529: 1549: 2247:"AFRICAN GENETIC DIVERSITY: Implications for Human Demographic History, Modern Human Origins, and Complex Disease Mapping" 2195:"African Genetic Diversity: Implications for Human Demographic History, Modern Human Origins, and Complex Disease Mapping" 273:) in the genetic sequence, but structural variations account for a greater number of base-pairs than the SNPs and indels. 8053: 549: 80:(who develop from one zygote) have infrequent genetic differences due to mutations occurring during development and gene 6568: 9625: 8691: 8474: 8450: 8373: 8114: 8089: 7999: 3580: 3551: 1952:

Lee, Jun-Ki; Aini, Rahmi Qurota; Sya’bandari, Yustika; Rusmana, Ai Nurlaelasari; Ha, Minsu; Shin, Sein (1 April 2021).

1146: 641: 593:, so they are used for personal or parental identification. Their analysis is useful in genetics and biology research, 545: 7567:

Relethford JH (August 2002). "Apportionment of global human genetic diversity based on craniometrics and skin color".

5578:"Colloquium paper: human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency" 4624: 541:(SNP) mutation. The study of haplogroups provides information about ancestral origins dating back thousands of years. 9303: 8784: 8736: 8663: 8445: 8440: 8266: 4865:. Vol. 4, Variability Within and Among Natural Populations. Chicago, Illinois: Univ. Chicago Press. p. 438. 4736: 2136:

Witherspoon, D. J.; Wooding, S.; Rogers, A. R.; Marchani, E. E.; Watkins, W. S.; Batzer, M. A.; Jorde, L. B. (2007).

1914: 1381:. CCR5 gene is absent on the surface of cell due to mutation. Without CCR5 gene on the surface, there is nothing for 1081:

Although the genetic differences among human groups are relatively small, these differences in certain genes such as

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complications after transplantation due to genetic variants in human leukocyte antigen (HLA) and non-HLA proteins.

4376:"Integrative analysis of RNA, translation, and protein levels reveals distinct regulatory variation across humans" 9181: 9110: 8879: 8535: 8486: 8430: 8173: 8136: 8084: 2838:"Challenges in the association of human single nucleotide polymorphism mentions with unique database identifiers" 2303:"We are all mutants: First direct whole-genome measure of human mutation predicts 60 new mutations in each of us" 1583:"Phenotypically concordant and discordant monozygotic twins display different DNA copy-number-variation profiles" 1507: 560:

line, from mother to both daughter or son. The Y-DNA and mtDNA may change by chance mutation at each generation.

9284: 8884: 8711: 8547: 8435: 8126: 1437: 1317: 1224: 1167: 538: 303: 297: 7234:"The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" 9457: 9243: 8621: 8256: 8183: 8140: 8119: 8104: 7774: 4563: 3115: 1544: 890:. Darker skin appears to be strongly selected for in equatorial regions to prevent sunburn, skin cancer, the 569: 460: 331: 6408:

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Genetic variation of Eurasian populations showing different frequency of West- and East-Eurasian components.

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A coding SNP is one that occurs inside a gene. There are 105 Human Reference SNPs that result in premature

327: 31: 5262:"Low levels of genetic divergence across geographically and linguistically diverse populations from India" 3195:"A DNA replication mechanism for generating nonrecurrent rearrangements associated with genomic disorders" 1581:

Bruder CE, Piotrowski A, Gijsbers AA, Andersson R, Erickson S, Diaz de Ståhl T, et al. (March 2008).

9396: 8859: 8636: 8616: 8361: 8339: 8094: 8072: 1529: 1482: 1094: 1064: 6638:"What we do and don't know about 'race', 'ethnicity', genetics and health at the dawn of the genome era" 6208:"Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies" 3788: 882:

A prominent exception to the common distribution of physical characteristics within and among groups is

805:

is to reduce gene flow between geographical groups and to increase the genetic distance between groups.

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Long JC, Kittles RA (August 2003). "Human genetic diversity and the nonexistence of biological races".

3911: 3446: 1938: 1819: 1001: 664: 84:. Differences between individuals, even closely related individuals, are the key to techniques such as 7514:

Ramachandran S, Deshpande O, Roseman CC, Rosenberg NA, Feldman MW, Cavalli-Sforza LL (November 2005).

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Keita SO, Kittles RA (1997). "The Persistence of Racial Thinking and the Myth of Racial Divergence".

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By these criteria, 1.6% of Perlegen SNPs were found to exhibit the genetic architecture of selection.

1534: 1291: 828: 605: 280:), which lists SNP and other variants, listed 324 million variants found in sequenced human genomes. 7795:

Weiss KM, Terwilliger JD (October 2000). "How many diseases does it take to map a gene with SNPs?".

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Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004).

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Ng PC, Levy S, Huang J, Stockwell TB, Walenz BP, Li K, et al. (August 2008). Schork NJ (ed.).

1492: 1211: 781: 228: 125:

to developing particular diseases. The greatest diversity is found within and among populations in

4737:"What We Know and What We Don't Know: Human Genetic Variation and the Social Construction of Race" 4327:"Genetic Control of Chromatin States in Humans Involves Local and Distal Chromosomal Interactions" 129:, and gradually declines with increasing distance from the African continent, consistent with the 9384: 9238: 8844: 8757: 8658: 8641: 8552: 8528: 8508: 8479: 8290: 7749: 7388: 5914:

Beleza S, Campos J, Lopes J, Araújo II, Hoppfer Almada A, Correia e Silva A, et al. (2012).

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Yu N, Jensen-Seaman MI, Chemnick L, Kidd JR, Deinard AS, Ryder O, Kidd KK, Li WH (August 2003).

936:

Wright himself believed that values >0.25 represent very great genetic variation and that an

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Tishkoff SA, Reed FA, Friedlaender FR, Ehret C, Ranciaro A, Froment A, et al. (May 2009).

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Dumas L, Kim YH, Karimpour-Fard A, Cox M, Hopkins J, Pollack JR, et al. (September 2007).

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DNA molecule 1 differs from DNA molecule 2 at a single base-pair location (a C/T polymorphism).

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1166:

different regions, are due to global variants. No genetic variants have been found which are

9207: 9071: 8965: 8960: 8864: 8611: 8378: 7877:"Haplotypes in the dystrophin DNA segment point to a mosaic origin of modern human diversity" 7232:

Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000).

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New findings show that each human has on average 60 new mutations compared to their parents.

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Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, et al. (February 2001).

6206:

Tang H, Quertermous T, Rodriguez B, Kardia SL, Zhu X, Brown A, et al. (February 2005).

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Conrad DF, Keebler JE, DePristo MA, Lindsay SJ, Zhang Y, Casals F, et al. (June 2011).

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Auton A, Brooks LD, Durbin RM, Garrison EP, Kang HM, Korbel JO, et al. (October 2015).

620: 552:, both of which can be used to define genetic populations. Y-DNA is passed solely along the 326:

difference between members of the species. About 3% to 5% of human SNPs are functional (see

9509: 9501: 9466: 9279: 9269: 9217: 8917: 8574: 8349: 8332: 7961: 7527: 7484: 7133: 7031: 6986: 6896: 6692: 6531: 6264: 5927: 5868: 5589: 5313: 5214: 5155: 5049: 4436: 4132: 4015: 3958: 3803: 3743: 3481: 3361: 3255: 2576: 2514: 2457: 2390: 1965: 1652: 1524: 1455: 1110: 1082: 481:

in a population to vary (become different) from one another. Variability is different from

403: 360: 355: 307: 266: 258: 7657:

Sankar P, Cho MK, Condit CM, Hunt LM, Koenig B, Marshall P, Lee SS, Spicer P (June 2004).

6841:"The role of community review in evaluating the risks of human genetic variation research" 6305: 6184: 5434: 5335:"A variant-centric perspective on geographic patterns of human allele frequency variation" 4325:

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Driscoll DA, Gross S (June 2009). "Clinical practice. Prenatal screening for aneuploidy".

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health-care professionals typically take these patterns into account in making diagnoses.

859: 219:

Genetic variation among humans occurs on many scales, from gross alterations in the human

107:

majority of variation exists within the members of each human population. For comparison,

8: 9544: 9520: 9212: 9186: 9161: 9145: 9061: 8937: 8824: 8800: 8598: 8398: 8261: 7022:

The International Hapmap Consortium (December 2003). "The International HapMap Project".

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Wu L, Candille SI, Choi Y, Xie D, Jiang L, Li-Pook-Than J, Tang H, Snyder M (July 2013).

2889:"Singleton SNPs in the human genome and implications for genome-wide association studies" 1417: 1195: 1075: 1055: 794:

has two important effects on the distribution of genetic variation. First, the so-called

764: 679: 579: 526: 472: 368: 179: 7531: 7488: 7137: 7035: 6990: 6900: 6696: 6535: 6268: 5931: 5872: 5823: 5593: 5218: 5159: 5053: 4515:"Common genetic variants account for differences in gene expression among ethnic groups" 4440: 4136: 4019: 3979: 3962: 3944: 3869: 3807: 3747: 3485: 3365: 3259: 2580: 2518: 2461: 2446:"Global genetic differentiation of complex traits shaped by natural selection in humans" 2394: 1656: 1016:(represented by the Papua New Guinean and Bougainville Islander) appears to derive from 402:

sequences which were amalgamations of sequences from many individuals, published by the

50: 9532: 9051: 9047: 8907: 7901: 7876: 7858: 7833: 7820: 7683: 7658: 7640: 7615: 7602: 7550: 7515: 7418: 7411: 7374: 7337: 7300: 7258: 7233: 7205: 7103: 7078: 7065: 7010: 6960: 6935: 6922: 6865: 6840: 6827: 6718: 6667: 6624: 6555: 6510: 6470: 6433: 6391: 6366: 6348: 6323: 6288: 6232: 6207: 6153: 6104: 6079: 6001: 5974: 5950: 5915: 5891: 5856: 5832: 5788: 5728: 5695: 5671: 5648: 5636: 5612: 5577: 5512: 5485: 5461: 5410: 5386:"Insights into human genetic variation and population history from 929 diverse genomes" 5385: 5361: 5334: 5288: 5261: 5237: 5202: 5178: 5143: 5119: 5094: 5070: 5037: 5010: 4977: 4953: 4920: 4901: 4834: 4707: 4682: 4605: 4539: 4514: 4457: 4424: 4400: 4375: 4351: 4326: 4307: 4246: 4221: 4202: 4158: 4098: 4085: 4060: 4036: 4003: 3916: 3882: 3824: 3764: 3731: 3679: 3382: 3349: 3325: 3300: 3276: 3243: 3224: 3088: 3061: 3007: 2980: 2956: 2929: 2864: 2837: 2769: 2744: 2597: 2564: 2563:

Kidd JM, Cooper GM, Donahue WF, Hayden HS, Sampas N, Graves T, et al. (May 2008).

2537: 2502: 2478: 2445: 2354: 2329: 2279: 2246: 2219: 2194: 2170: 2137: 2116: 2064: 1991: 1932: 1760: 1673: 1640: 1607: 1582: 1472: 1313: 1309: 997: 979: 887: 864: 802: 598: 138: 7726: 7701: 6756: 6731: 6587: 6055: 6028: 3494: 3469: 3060:

Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007).

2421: 2378: 1869: 95:(bp) across 46 chromosomes of DNA as well as slightly under 17,000 bp DNA in cellular 9338: 9166: 9126: 9042: 9037: 8975: 8902: 8894: 8869: 8586: 8562: 8467: 8388: 8383: 8251: 7965: 7944: 7918: 7906: 7863: 7812: 7731: 7688: 7645: 7594: 7555: 7502: 7459: 7422: 7366: 7329: 7292: 7263: 7197: 7161: 7108: 7057: 7002: 6965: 6914: 6870: 6819: 6790: 6761: 6722: 6710: 6659: 6616: 6591: 6547: 6502: 6462: 6425: 6396: 6353: 6306:

Interpreting polygenic scores, polygenic adaptation, and human phenotypic differences

6280: 6237: 6188: 6145: 6109: 6060: 6006: 5955: 5896: 5837: 5780: 5772: 5733: 5715: 5676: 5617: 5517: 5466: 5415: 5366: 5293: 5242: 5183: 5124: 5075: 5015: 4997: 4958: 4940: 4893: 4820: 4789: 4712: 4544: 4462: 4405: 4356: 4297: 4251: 4192: 4150: 4090: 4041: 3984: 3874: 3829: 3769: 3671: 3576: 3547: 3499: 3418: 3387: 3330: 3301:"Gene copy number variation spanning 60 million years of human and primate evolution" 3281: 3216: 3093: 3012: 2961: 2910: 2869: 2818: 2774: 2725: 2681: 2637: 2602: 2542: 2483: 2426: 2408: 2359: 2284: 2266: 2224: 2175: 2157: 2104: 2094: 2052: 2042: 1995: 1983: 1920: 1910: 1881: 1873: 1827: 1800: 1783:

Curnoe, Darren (2003). "Number of ancestral human species: a molecular perspective".

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self-identified race can be used as an indicator of geographic ancestry for certain

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There are at least three reasons why genetic variation exists between populations.

117: 7939: 7922: 7849: 7824: 5711: 695:

during human migration, which are events that temporarily reduce population size.

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5940: 5502: 5435:"Dating genomic variants and shared ancestry in population-scale sequencing data" 5278: 5093:

Wall JD, Yang MA, Jay F, Kim SK, Durand EY, Stevison LS, et al. (May 2013).

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Who we are and how we got here: ancient DNA and the new science of the human past

1467: 1443: 1362: 1303: 1138: 1130: 868: 740: 736: 534: 498: 407: 395: 187:, which is the effect of random changes in the gene pool, under conditions where 6421: 6324:"The use of racial, ethnic, and ancestral categories in human genetics research" 6095: 5110: 4993: 4936: 4220:

Bamshad MJ, Wooding S, Watkins WS, Ostler CT, Batzer MA, Jorde LB (March 2003).

2153: 9420: 9066: 9056: 8970: 8849: 8313: 7702:"Evidence for gradients of human genetic diversity within and among continents" 7520: