31:
247:
with sophisticated body plans, i.e. bilaterians. There are several theories on the origin of the strict germline-soma distinction. Setting aside an isolated germ cell population early in embryogenesis might promote cooperation between the somatic cells of a complex multicellular organism. Another recent theory suggests that early germline sequestration evolved to limit the accumulation of deleterious mutations in mitochondrial genes in complex organisms with high energy requirements and fast mitochondrial mutation rates.
48:
330:
155:. Apomixis and Parthenogenesis both refer to the development of an embryo without fertilization. The former typically occurs in plants seeds, while the latter tends to be seen in nematodes, as well as certain species of reptiles, birds, and fish. Autogamy is a term used to describe self pollination in plants. Cloning is a technique used to creation of genetically identical cells or organisms.
369:
In the mouse, by days 6.25 to 7.25 after fertilization of an egg by a sperm, cells in the embryo are set aside as primordial germ cells (PGCs). These PGCs will later give rise to germline sperm cells or egg cells. At this point the PGCs have high typical levels of methylation. Then primordial germ
246:
Plants and basal metazoans such as sponges (Porifera) and corals (Anthozoa) do not sequester a distinct germline, generating gametes from multipotent stem cell lineages that also give rise to ordinary somatic tissues. It is therefore likely that germline sequestration first evolved in complex animals
199:
proposed and pointed out, a germline cell is immortal in the sense that it is part of a lineage that has reproduced indefinitely since the beginning of life and, barring accident, could continue doing so indefinitely. However, it is now known in some detail that this distinction between somatic and
365:
regions of genes can reduce or silence gene expression. About 28 million CpG dinucleotides occur in the human genome, and about 24 million CpG sites in the mouse genome (which is 86% as large as the human genome). In most tissues of mammals, on average, 70% to 80% of CpG cytosines are methylated
603:
Bonetti, G., Donato, K., Medori, M. C., Dhuli, K., Henehan, G., Brown, R., Sieving, P., Sykora, P., Marks, R., Falsini, B., Capodicasa, N., Miertus, S., Lorusso, L., Dondossola, D., Tartaglia, G. M., Cerkez
Ergoren, M., Dundar, M., Michelini, S., Malacarne, D., Beccari, T., … Bertelli, M. (2023).
401:
Following erasure of DNA methylation marks in mouse PGCs, male and female germ cells undergo new methylation at different time points during gametogenesis. While undergoing mitotic expansion in the developing gonad, the male germline starts the re-methylation process by embryonic day 14.5. The
386:
all genomic sequences. This loss of methylation occurs through passive demethylation due to repression of the major components of the methylation machinery. The second phase occurs during embryonic days 9.5 to 13.5 and causes demethylation of most remaining specific loci, including
395:(5-hmC) during embryonic days 9.5 to 10.5. This is likely followed by replication-dependent dilution during embryonic days 11.5 to 13.5. At embryonic day 13.5, PGC genomes display the lowest level of global DNA methylation of all cells in the life cycle.
675:
Akira Wakana and
Shunpei Uemoto. Adventive Embryogenesis in Citrus (Rutaceae). II. Postfertilization Development. American Journal of Botany Vol. 75, No. 7 (Jul., 1988), pp. 1033-1047 Published by: Botanical Society of America Article Stable URL:
381:
In the mouse, PGCs undergo DNA demethylation in two phases. The first phase, starting at about embryonic day 8.5, occurs during PGC proliferation and migration, and it results in genome-wide loss of methylation, involving
333:
5 methylcytosine methyl highlight. The image shows a cytosine single ring base and a methyl group added on to the 5 carbon. In mammals, DNA methylation occurs almost exclusively at a cytosine that is followed by a
219:
into somatic and germ lines, but in the absence of specialised technical human intervention practically all but the simplest multicellular structures do so. In such organisms somatic cells tend to be practically
402:
sperm-specific methylation pattern is maintained during mitotic expansion. DNA methylation levels in primary oocytes before birth remain low, and re-methylation occurs after birth in the oocyte growth phase.
166:, recombinations and other genetic changes in the germline may be passed to offspring, but changes in a somatic cell will not be. This need not apply to somatically reproducing organisms, such as some
398:
In the mouse, the great majority of differentially expressed genes in PGCs from embryonic day 9.5 to 13.5, when most genes are demethylated, are upregulated in both male and female PGCs.
1042:
Bernstein H, Byerly HC, Hopf FA, Michod RE. Genetic damage, mutation, and the evolution of sex. Science. 1985 Sep 20;229(4719):1277-81. doi: 10.1126/science.3898363. PMID 3898363
345:
of DNA include modifications that affect gene expression, but are not caused by changes in the sequence of bases in DNA. A well-studied example of such an alteration is the
230:
can refer to a lineage of cells spanning many generations of individuals—for example, the germline that links any living individual to the hypothetical
547:
Dudgeon, C. L., Coulton, L., Bone, R., Ovenden, J. R., & Thomas, S. (2017). Switch from sexual to parthenogenetic reproduction in a zebra shark.
224:, and for over a century sponge cells have been known to reassemble into new sponges after having been separated by forcing them through a sieve.
317:. Among humans, about five percent of live-born offspring have a genetic disorder, and of these, about 20% are due to newly arisen
628:
700:
516:
493:
278:, is produced by spontaneous oxidation in the germline cells of mice, and during the cell's DNA replication cause GC to TA
626:. ed. E.Monosson and C.J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC
195:
In an earlier stage of genetic thinking, there was a clear distinction between germline and somatic cells. For example,
660:
305:. The lower frequencies of mutation in germline cells compared to somatic cells appears to be due to more efficient
259:
875:
Ohno M, Sakumi K, Fukumura R, Furuichi M, Iwasaki Y, Hokama M, Ikemura T, Tsuzuki T, Gondo Y, Nakabeppu Y (2014).
200:
germ cells is partly artificial and depends on particular circumstances and internal cellular mechanisms such as
582:
30:
1333:
231:
293:
The mutation frequencies for cells in different stages of gametogenesis are about 5 to 10-fold lower than in
566:
258:(ROS) are produced as byproducts of metabolism. In germline cells, ROS are likely a significant cause of
466:
Zickler, D., & Kleckner, N. (2015). Recombination, Pairing, and
Synapsis of Homologs during Meiosis.
449:
Yao, C., Yao, R., Luo, H., & Shuai, L. (2022). Germline specification from pluripotent stem cells.
421:
387:
germline-specific and meiosis-specific genes. This second phase of demethylation is mediated by the
57:, an example of a sponge that can grow indefinitely from somatic tissue and reconstitute itself from
17:
567:"Contributions of Autogamy and Geitonogamy to Self-Fertilization in a Mass-Flowering, Clonal Plant"
310:
216:
530:
Niccolò, T., Anderson, A. W., & Emidio, A. (2023). Apomixis: oh, what a tangled web we have!.
1183:
Jabbari K, Bernardi G (May 2004). "Cytosine methylation and CpG, TpG (CpA) and TpA frequencies".
392:
255:
27:
Population of a multicellular organism's cells that pass on their genetic material to the progeny
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Radzvilavicius, Arunas L.; Hadjivasiliou, Zena; Pomiankowski, Andrew; Lane, Nick (2016-12-20).
78:
124:
Germ cells pass on genetic material through the process of sexual reproduction. This includes
416:
129:
937:"Mutation frequency declines during spermatogenesis in young mice but increases in old mice"
690:
948:
888:
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8:
1338:
1281:"Dynamics of 5-methylcytosine and 5-hydroxymethylcytosine during germ cell reprogramming"
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TET1 and TET2, which carry out the first step in demethylation by converting 5-mC to
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In sexually reproducing organisms, cells that are not in the germline are called
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Proceedings of the
National Academy of Sciences of the United States of America
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Watt, F. M. and B. L. M. Hogan. 2000 Out of Eden: Stem Cells and Their Niches
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Fertilization in protozoa and metazoan animals: cellular and molecular aspects
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371:
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125:
47:
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Yamaguchi S, Hong K, Liu R, Inoue A, Shen L, Zhang K, Zhang Y (March 2013).
1095:"DNA methylation in human epigenomes depends on local topology of CpG sites"
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114:
900:
751:"Selection for Mitochondrial Quality Drives Evolution of the Germline"
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302:
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184:
106:
82:
877:"8-oxoguanine causes spontaneous de novo germline mutations in mice"
358:
354:
267:
175:
163:
148:
140:
136:. These processes help to increase genetic diversity in offspring.
90:
70:
52:
41:
994:
Murphey P, McLean DJ, McMahan CA, Walter CA, McCarrey JR (2013).
935:
Walter CA, Intano GW, McCarrey JR, McMahan CA, Walter RB (1998).
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117:, which develop into the final gametes. This process is known as
66:
171:
167:
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86:
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from CpG to 5-mCpG. Methylation of cytosines in CpG sites in
102:
94:
1227:"DNA Methylation Reprogramming during Mammalian Development"
508:
Lowe, Andrew; Harris, Stephen; Ashton, Paul (1 April 2000).
139:
Certain organisms reproduce asexually via processes such as
934:
612:(Suppl 2(6)), 230–235. https://doi.org/10.7417/CT.2023.2492
583:
10.1890/0012-9658(2000)081[0532:COAAGT]2.0.CO;2
1092:
993:
874:
604:
Human
Cloning: Biology, Ethics, and Social Implications.
474:(6), a016626. https://doi.org/10.1101/cshperspect.a016626
1093:
Lövkvist C, Dodd IB, Sneppen K, Haerter JO (June 2016).
510:
Ecological
Genetics: Design, Analysis, and Application
374:, followed by subsequent new methylation to reset the
282:
mutations. Such mutations occur throughout the mouse
1278:
810:"Evolution, development, and the units of selection"
719:
Essays upon heredity and kindred biological problems
538:(5), 92. https://doi.org/10.1007/s00425-023-04124-0
457:(1), 74. https://doi.org/10.1186/s13287-022-02750-1
648:
250:
204:and controls such as the selective application of
1325:
1054:"DNA methylation patterns and epigenetic memory"
996:"Enhanced genetic integrity in mouse germ cells"
170:and many plants. For example, many varieties of
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715:
85:. In other words, they are the cells that form
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577:(2). Ecological Society of America: 532–542.
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647:Brusca, Richard C.; Brusca, Gary J. (1990).
484:TarĂn, Juan J.; Cano, Antonio, eds. (2000).
925:
370:cells of the mouse undergo genome-wide DNA
353:. This usually occurs in the DNA sequence
188:, produce seeds apomictically when somatic
555:, 40537. https://doi.org/10.1038/srep40537
468:Cold Spring Harbor perspectives in biology
192:cells displace the ovule or early embryo.
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565:Eckert, Christopher G. (February 2000).
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286:as well as during different stages of
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695:. New India Publishing. pp. 9–.
97:), which can come together to form a
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678:https://www.jstor.org/stable/2443771
234:, from which all plants and animals
24:
739:
655:. Sunderland: Sinauer Associates.
378:in order to form an egg or sperm.
25:
1350:
689:K V Ed Peter (5 February 2009).
593:– via John Wiley and Sons.
451:Stem cell research & therapy
215:Not all multicellular organisms
162:. According to this definition,
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488:. Berlin Heidelberg: Springer.
251:DNA damage, mutation and repair
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232:last universal common ancestor
13:
1:
1225:Zeng Y, Chen T (March 2019).
1012:10.1095/biolreprod.112.103481
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309:of DNA damages, particularly
941:Proc. Natl. Acad. Sci. U.S.A
768:10.1371/journal.pbio.2000410
274:, an oxidized derivative of
241:
101:. They differentiate in the
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1142:Guénet JL (December 2005).
405:
81:'s cells that develop into
10:
1355:
1197:10.1016/j.gene.2004.02.043
422:Germinal choice technology
357:, changing the DNA at the
311:homologous recombinational
512:. John Wiley & Sons.
962:10.1073/pnas.95.17.10015
808:Buss, L W (1983-03-01).
716:August Weismann (1892).
349:of DNA cytosine to form
313:repair, during germline
1052:Bird A (January 2002).
631:April 30, 2011, at the
621:C.Michael Hogan. 2010.
393:5-hydroxymethylcytosine
256:Reactive oxygen species
77:is the population of a
61:separated somatic cells
835:10.1073/pnas.80.5.1387
692:Basics Of Horticulture
606:La Clinica terapeutica
343:Epigenetic alterations
339:
325:Epigenetic alterations
79:multicellular organism
62:
44:
1334:Developmental biology
1244:10.3390/genes10040257
734:Science 287:1427-1430
417:Germ line development
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113:, which develop into
107:primordial germ cells
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33:
953:1998PNAS...9510015W
893:2014NatSR...4E4689O
826:1983PNAS...80.1387B
1297:10.1038/cr.2013.22
1161:10.1101/gr.3728305
1144:"The mouse genome"
1111:10.1093/nar/gkw124
1071:10.1101/gad.947102
722:. Clarendon press.
549:Scientific reports
366:(forming 5-mCpG).
340:
319:germline mutations
63:
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1099:Nucleic Acids Res
901:10.1038/srep04689
702:978-81-89422-55-4
518:978-1-444-31121-1
495:978-3-540-67093-3
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34:Cormlets of
1064:(1): 6–21.
412:Epigenetics
389:TET enzymes
347:methylation
284:chromosomes
262:that, upon
260:DNA damages
115:gametocytes
111:gametogonia
1339:Germ cells
1328:Categories
1237:(4): 257.
1148:Genome Res
438:References
307:DNA repair
266:, lead to
222:totipotent
210:stem cells
206:telomerase
182:, such as
180:Asteraceae
83:germ cells
59:totipotent
1191:: 143–9.
1058:Genes Dev
844:0027-8424
777:1545-7885
591:0012-9658
376:epigenome
303:oogenesis
297:both for
268:mutations
242:Evolution
202:telomeres
185:Taraxacum
164:mutations
18:Germ line
1315:23399596
1285:Cell Res
1263:30934924
1205:15177689
1170:16339371
1129:26932361
1080:11782440
1030:23153565
1006:(1): 6.
919:24732879
887:: 4689.
795:27997535
629:Archived
624:Mutation
406:See also
363:promoter
359:CpG site
228:Germline
176:Rosaceae
168:Porifera
149:autogamy
141:apomixis
75:germline
71:genetics
55:tuberosa
53:Clathria
42:apomixis
1306:3587712
1254:6523607
1120:4914085
1021:4434944
981:9707592
949:Bibcode
910:3986730
889:Bibcode
881:Sci Rep
862:6572396
822:Bibcode
786:5172535
571:Ecology
336:guanine
315:meiosis
276:guanine
236:descend
190:diploid
153:cloning
134:meiosis
87:gametes
67:biology
1313:
1303:
1261:
1251:
1203:
1168:
1127:
1117:
1078:
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1018:
979:
969:
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853:393602
850:
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532:Planta
492:
384:almost
172:citrus
151:, and
103:gonads
99:zygote
73:, the
972:21453
109:into
105:from
95:sperm
1311:PMID
1259:PMID
1201:PMID
1185:Gene
1166:PMID
1125:PMID
1076:PMID
1026:PMID
977:PMID
915:PMID
858:PMID
840:ISSN
791:PMID
773:ISSN
697:ISBN
657:ISBN
587:ISSN
514:ISBN
490:ISBN
301:and
132:and
93:and
91:eggs
69:and
1301:PMC
1293:doi
1249:PMC
1239:doi
1193:doi
1189:333
1156:doi
1115:PMC
1107:doi
1066:doi
1016:PMC
1008:doi
967:PMC
957:doi
905:PMC
897:doi
848:PMC
830:doi
781:PMC
763:doi
610:174
579:doi
536:257
355:CpG
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