81:
200:
242:, CO recombination may help ensure the orderly segregation of the paired homologous chromosomes to opposite poles. In support of this, a study of aneuploidy in single spermatozoa by whole genome sequencing found that, on average, human sperm cells with aneuploid autosomes exhibit significantly fewer crossovers than normal cells. After the first chromosome segregation in
212:
recombination is thought to occur by the Double
Holliday Junction (DHJ) model, illustrated on the right, above. NCO recombinants are thought to occur primarily by the Synthesis Dependent Strand Annealing (SDSA) model, illustrated on the left, above. Most recombination events appear to be the SDSA type.
353:
showed a 30% genome-wide reduction in crossover numbers, and a large number of meioses with non-exchange chromosomes. Nevertheless, this mutant gave rise to spore viability patterns suggesting that segregation of non-exchange chromosomes occurred efficiently. Thus it appears that CO recombination
309:
double-stranded DNA, and promotes the formation of CO recombinants. Double mutants deleted for both MLH3 (major pathway) and MMS4 (which is necessary for a minor
Holliday junction resolution pathway) showed dramatically reduced crossing over compared to wild-type (6- to 17-fold reduction); however
211:
A current model of meiotic recombination, initiated by a double-strand break or gap, followed by pairing with an homologous chromosome and strand invasion to initiate the recombinational repair process. Repair of the gap can lead to crossover (CO) or non-crossover (NCO) of the flanking regions. CO
179:(see meiosis diagram). During this stage, segregation occurs by a process similar to that during mitosis, except that in this case prophase II is not preceded by a round of DNA replication. Thus the two chromatids comprising each chromosome separate into different
133:
of different parental origin (e.g. a paternal and a maternal set). During the phase of meiosis labeled “interphase s” in the meiosis diagram there is a round of DNA replication, so that each of the chromosomes initially present is now composed of two copies called
1013:
Bocker T, Barusevicius A, Snowden T, Rasio D, Guerrette S, Robbins D, Schmidt C, Burczak J, Croce CM, Copeland T, Kovatich AJ, Fishel R (1999). "hMSH5: a human MutS homologue that forms a novel heterodimer with hMSH4 and is expressed during spermatogenesis".
138:. These chromosomes (paired chromatids) then pair with the homologous chromosome (also paired chromatids) present in the same nucleus (see prophase I in the meiosis diagram). The process of alignment of paired homologous chromosomes is called synapsis (see
100:
chromosome segregation occurs routinely as a step in cell division (see mitosis diagram). As indicated in the mitosis diagram, mitosis is preceded by a round of DNA replication, so that each chromosome forms two copies called
250:. Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in meiosis II are required to generate gametes with the correct number of chromosomes.
191:. Failure of proper segregation during prophase II can also lead to aneuploid gametes. Aneuploid gametes can undergo fertilization to form aneuploid zygotes and hence to serious adverse consequences for progeny.
109:. Upon proper segregation, a complete set of chromatids ends up in each of two nuclei, and when cell division is completed, each DNA copy previously referred to as a chromatid is now called a chromosome.
72:. However, in contrast to eukaryotic chromosome segregation, replication and segregation are not temporally separated. Instead segregation occurs progressively following replication.
146:(involving physical exchange between two chromatids), but most recombination events involve information exchange but not physical exchange between two chromatids (see
367:
has the ability to segregate homologous chromosomes in the absence of meiotic recombination (achiasmate segregation). This ability depends on the microtubule motor
147:
257:
intermediates. As indicated in the figure titled "A current model of meiotic recombination", the formation of meiotic crossovers can be initiated by a
626:"Activation of an alternative, rec12 (spo11)-independent pathway of fission yeast meiotic recombination in the absence of a DNA flap endonuclease"
208:
1046:"Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in Saccharomyces cerevisiae"
389:
265:-like protein SPO11. CO recombination may also be initiated by external sources of DNA damage such as X-irradiation, or internal sources.
150:). Following recombination, chromosome segregation occurs as indicated by the stages metaphase I and anaphase I in the meiosis diagram.
230:, CO recombination provides a physical link that holds homologous chromosome pairs together. These linkages are established by
183:, so that each nucleus gets a single set of chromatids (now called chromosomes) and each nucleus becomes included in a haploid
577:"Meiotic recombination in C. elegans initiates by a conserved mechanism and is dispensable for homologous chromosome synapsis"
286:
resolution were found to efficiently undergo proper chromosome segregation. The pathway that produces the majority of COs in
881:"Genetic analysis of mlh3 mutations reveals interactions between crossover promoting factors during meiosis in baker's yeast"
268:
There is evidence that CO recombination facilitates meiotic chromosome segregation. Other studies, however, indicate that
974:"Cloning and characterization of the human and Caenorhabditis elegans homologs of the Saccharomyces cerevisiae MSH5 gene"
776:"The Saccharomyces cerevisiae Mlh1-Mlh3 heterodimer is an endonuclease that preferentially binds to Holliday junctions"
469:
Lu S, Zong C, Fan W, Yang M, Li J, Chapman AR, Zhu P, Hu X, Xu L, Yan L, Bai F, Qiao J, Tang F, Li R, Xie XS (2012).
363:
1153:
274:
157:. This process results in each gamete usually containing a mixture of chromosomes from both original parents.
349:
and promotes their resolution into crossover products. An MSH4 hypomorphic (partially functional) mutant of
187:(see stages following prophase II in the meiosis diagram). This segregation process is also facilitated by
105:. These chromatids separate to opposite poles, a process facilitated by a protein complex referred to as
724:"Delineation of joint molecule resolution pathways in meiosis identifies a crossover-specific resolvase"
342:
223:
219:
154:
143:
130:
53:
827:"Mlh1-Mlh3, a meiotic crossover and DNA mismatch repair factor, is a Msh2-Msh3-stimulated endonuclease"
142:). During synapsis, genetic recombination usually occurs. Some of the recombination events occur by
1148:
673:
Pauklin S, Burkert JS, Martin J, Osman F, Weller S, Boulton SJ, Whitby MC, Petersen-Mahrt SK (2009).
482:
1158:
528:"Connecting by breaking and repairing: mechanisms of DNA strand exchange in meiotic recombination"
606:
269:
231:
165:
471:"Probing meiotic recombination and aneuploidy of single sperm cells by whole-genome sequencing"
1124:
1075:
1023:
995:
954:
910:
858:
807:
753:
704:
655:
598:
557:
508:
448:
430:
372:
346:
283:
254:
246:
is complete, there is further chromosome segregation during the second equational division of
1114:
1106:
1065:
1057:
985:
944:
900:
892:
848:
838:
797:
787:
743:
735:
694:
686:
645:
637:
588:
547:
539:
498:
490:
438:
422:
272:, while supportive, are not essential to meiotic chromosome segregation. The budding yeast
675:"Alternative induction of meiotic recombination from single-base lesions of DNA deaminases"
207:
49:
28:
486:
1119:
1094:
1070:
1045:
905:
880:
853:
826:
802:
775:
748:
723:
699:
674:
650:
625:
552:
527:
503:
470:
443:
410:
315:
161:
153:
Different pairs of chromosomes segregate independently of each other, a process termed
17:
593:
576:
301:(called MutL gamma). MLH1-MLH3 binds preferentially to Holliday junctions. It is an
1142:
330:
306:
298:
262:
610:
253:
CO recombinants are produced by a process involving the formation and resolution of
302:
180:
89:
57:
411:"Dynamics of Escherichia coli Chromosome Segregation during Multifork Replication"
1044:
Krishnaprasad GN, Anand MT, Lin G, Tekkedil MM, Steinmetz LM, Nishant KT (2015).
575:
Dernburg AF, McDonald K, Moulder G, Barstead R, Dresser M, Villeneuve AM (1998).
1110:
1061:
690:
641:
739:
234:, which are the cytological manifestations of CO recombination. Together with
384:
258:
199:
169:
85:
69:
949:
932:
434:
843:
792:
494:
239:
135:
102:
80:
45:
41:
1128:
1079:
1027:
990:
973:
933:"Conserved properties between functionally distinct MutS homologs in yeast"
914:
862:
811:
757:
708:
659:
561:
512:
452:
999:
958:
896:
602:
278:
is a model organism used for studying meiotic recombination. Mutants of
139:
426:
290:, and possibly in mammals, involves a complex of proteins including the
825:
Rogacheva MV, Manhart CM, Chen C, Guarne A, Surtees J, Alani E (2014).
543:
247:
243:
235:
227:
216:
188:
176:
126:
122:
118:
106:
97:
65:
61:
409:
Nielsen, H. J.; Youngren, B.; Hansen, F. G.; Austin, S. (2007-12-01).
1095:"Dynein promotes achiasmate segregation in Schizosaccharomyces pombe"
368:
184:
345:
during meiosis. The MSH4/MSH5 complex binds and stabilizes double
341:, MSH4 and MSH5 act specifically to facilitate crossovers between
311:
198:
79:
326:
322:
295:
291:
129:(see meiosis diagram). In a diploid cell there are two sets of
56:, separate from each other and migrate to opposite poles of the
371:
that regulates the movement of chromosomes to the poles of the
175:
The second stage at which segregation occurs during meiosis is
879:
Sonntag Brown M, Lim E, Chen C, Nishant KT, Alani E (2013).
354:
facilitates proper chromosome segregation during meiosis in
117:
Chromosome segregation occurs at two separate stages during
624:
Farah JA, Cromie G, Davis L, Steiner WW, Smith GR (2005).
261:(DSB). The introduction of DSBs in DNA often employs the
222:(CO) recombination facilitates the proper segregation of
195:
Crossovers facilitate segregation, but are not essential
172:
gametes having either too few or too many chromosomes.
155:“independent assortment of non-homologous chromosomes”
314:
viability was reasonably high (62%) and chromosomal
931:Pochart P, Woltering D, Hollingsworth NM (1997).
1039:
1037:
722:Zakharyevich K, Tang S, Ma Y, Hunter N (2012).
282:defective in CO recombination at the level of
60:. This segregation process occurs during both
329:proteins form a hetero-oligomeric structure (
8:
113:Meiotic chromosome and chromatid segregation
148:Synthesis-dependent strand annealing (SDSA)
972:Winand NJ, Panzer JA, Kolodner RD (1998).
926:
924:
874:
872:
226:. This is because, at the end of meiotic
1118:
1069:
989:
948:
904:
852:
842:
801:
791:
747:
698:
649:
592:
551:
502:
442:
769:
767:
206:
68:. Chromosome segregation also occurs in
401:
390:Non-random segregation of chromosomes
160:Improper chromosome segregation (see
7:
464:
462:
774:Ranjha L, Anand R, Cejka P (2014).
305:that makes single-strand breaks in
25:
203:A diagram of the meiotic phases
1:
594:10.1016/s0092-8674(00)81481-6
76:Mitotic chromatid segregation
885:G3: Genes, Genomes, Genetics
526:Sansam CL, Pezza RJ (2015).
318:appeared mostly functional.
1111:10.1534/genetics.104.040253
1062:10.1534/genetics.114.172320
691:10.1534/genetics.109.101683
642:10.1534/genetics.105.046821
358:, but it is not essential.
48:formed as a consequence of
1175:
1093:Davis L, Smith GR (2005).
740:10.1016/j.cell.2012.03.023
26:
364:Schizosaccharomyces pombe
950:10.1074/jbc.272.48.30345
275:Saccharomyces cerevisiae
27:Not to be confused with
844:10.1074/jbc.M113.534644
793:10.1074/jbc.M113.533810
495:10.1126/science.1229112
415:Journal of Bacteriology
238:linkage between sister
18:Chromosomal segregation
991:10.1006/geno.1998.5447
343:homologous chromosomes
224:homologous chromosomes
213:
204:
131:homologous chromosomes
93:
54:homologous chromosomes
38:Chromosome segregation
897:10.1534/g3.112.004622
220:chromosomal crossover
210:
202:
83:
84:Mitosis divides the
44:by which two sister
487:2012Sci...338.1627L
427:10.1128/JB.01212-07
259:double-strand break
544:10.1111/febs.13317
361:The fission yeast
347:Holliday junctions
214:
205:
94:
40:is the process in
34:Biological process
481:(6114): 1627–30.
421:(23): 8660–8666.
284:Holliday junction
255:Holliday junction
16:(Redirected from
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337:and humans. In
168:) can result in
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1154:DNA replication
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1043:
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1035:
1012:
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1007:
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943:(48): 30345–9.
930:
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878:
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870:
824:
823:
819:
773:
772:
765:
721:
720:
716:
672:
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667:
636:(4): 1499–511.
623:
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574:
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569:
538:(13): 2444–57.
525:
524:
520:
468:
467:
460:
408:
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398:
381:
373:meiotic spindle
197:
162:non-disjunction
115:
78:
50:DNA replication
35:
32:
29:Sex segregation
23:
22:
15:
12:
11:
5:
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1085:
1056:(2): 399–412.
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1005:
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868:
837:(9): 5664–73.
817:
786:(9): 5674–86.
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1105:(2): 581–90.
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1059:
1055:
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1022:(4): 816–22.
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937:J. Biol. Chem
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831:J. Biol. Chem
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780:J. Biol. Chem
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734:(2): 334–47.
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587:(3): 387–98.
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541:
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356:S. cerevisiae
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351:S. cerevisiae
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339:S. cerevisiae
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335:S. cerevisiae
332:
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288:S. cerevisiae
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280:S. cerevisiae
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263:topoisomerase
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144:crossing over
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43:
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30:
19:
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1015:
1008:
984:(1): 69–80.
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977:
967:
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936:
888:
884:
834:
830:
820:
783:
779:
731:
727:
717:
685:(1): 41–54.
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633:
629:
619:
584:
580:
570:
535:
531:
521:
478:
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320:
303:endonuclease
287:
279:
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215:
174:
159:
152:
116:
95:
90:cell nucleus
52:, or paired
37:
36:
1149:Chromosomes
891:(1): 9–22.
331:heterodimer
316:disjunction
307:supercoiled
299:heterodimer
177:prophase II
127:anaphase II
86:chromosomes
70:prokaryotes
1159:Cell cycle
1143:Categories
1016:Cancer Res
396:References
385:Cell cycle
248:meiosis II
240:chromatids
228:prophase I
136:chromatids
123:anaphase I
103:chromatids
46:chromatids
42:eukaryotes
435:0021-9193
244:meiosis I
232:chiasmata
170:aneuploid
1129:15802518
1099:Genetics
1080:25467183
1050:Genetics
1028:10029069
978:Genomics
915:23316435
863:24403070
812:24443562
758:22500800
709:19237686
679:Genetics
660:16118186
630:Genetics
611:10198891
562:25953379
513:23258895
453:17905986
379:See also
236:cohesion
140:Synapsis
1120:1450395
1071:4317650
1000:9787078
959:9374523
906:3538346
854:3937641
803:3937642
749:3377385
700:2674839
651:1456079
603:9708740
553:4573575
504:3590491
483:Bibcode
475:Science
444:2168957
270:chiasma
217:Meiotic
189:cohesin
121:called
119:meiosis
107:cohesin
98:mitosis
96:During
66:meiosis
62:mitosis
58:nucleus
1127:
1117:
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1026:
998:
957:
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707:
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658:
648:
609:
601:
560:
550:
532:FEBS J
511:
501:
451:
441:
433:
369:dynein
185:gamete
181:nuclei
166:disomy
607:S2CID
333:) in
312:spore
88:in a
1125:PMID
1076:PMID
1024:PMID
996:PMID
955:PMID
911:PMID
859:PMID
808:PMID
754:PMID
728:Cell
705:PMID
656:PMID
599:PMID
581:Cell
558:PMID
509:PMID
449:PMID
431:ISSN
327:MSH5
325:and
323:MSH4
321:The
296:MLH3
292:MLH1
125:and
64:and
1115:PMC
1107:doi
1103:170
1066:PMC
1058:doi
1054:199
986:doi
945:doi
941:272
901:PMC
893:doi
849:PMC
839:doi
835:289
798:PMC
788:doi
784:289
744:PMC
736:doi
732:149
695:PMC
687:doi
683:182
646:PMC
638:doi
634:171
589:doi
548:PMC
540:doi
536:282
499:PMC
491:doi
479:338
439:PMC
423:doi
419:189
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