Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg)
Sex and meiosis were studied in induced autotetraploids of the Pacific oyster (Crassostrea gigas Thunberg) and were compared with sex and meiosis in autotriploids and normal diploids. Tetraploid oysters reached sexual maturity at 1 year of age in an approximately 1:1 sex ratio. In contrast with the...
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Canadian Science Publishing
1997
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crcansciencepubl:10.1139/g97-053 2024-09-09T19:37:17+00:00 Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) Guo, Ximing Allen Jr., Standish K. 1997 http://dx.doi.org/10.1139/g97-053 http://www.nrcresearchpress.com/doi/pdf/10.1139/g97-053 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Genome volume 40, issue 3, page 397-405 ISSN 0831-2796 1480-3321 journal-article 1997 crcansciencepubl https://doi.org/10.1139/g97-053 2024-08-01T04:10:03Z Sex and meiosis were studied in induced autotetraploids of the Pacific oyster (Crassostrea gigas Thunberg) and were compared with sex and meiosis in autotriploids and normal diploids. Tetraploid oysters reached sexual maturity at 1 year of age in an approximately 1:1 sex ratio. In contrast with the abnormally high frequency of hermaphrodites among triploids, tetraploids had about the same level of hermaphrodites as normal diploids. Fecundity of tetraploids was comparable to that of normal diploids, differing from the greatly reduced fecundity of triploids. Homologous chromosomes synapsed predominantly as trivalents in eggs from triploids and as quadrivalents in eggs from tetraploids. After fertilization, eggs from tetraploids and triploids went through two meiotic divisions, as normal eggs did. The average gamete chromosome number was 10.0 for diploids and 19.9 for tetraploids. The distribution of gamete chromosome numbers from triploids suggested that the extra chromosome in the trivalent segregated randomly during anaphase I. In tetraploids, however, the two extra chromosomes in the quadrivalents did not segregate independently and, instead, they preferentially cosegregated to opposite poles producing balanced gametes. These results suggest that mechanisms may exist to weigh, balance, and equally distribute quadrivalents, possibly through mitotic force and tension. Errors in chromosome balancing in normal meiosis may result in nondisjunction, which is the primary cause of human aneuploidy.Key words: sex, meiosis, multivalent segregation, polyploidy, aneuploidy, Crassostrea gigas. Article in Journal/Newspaper Crassostrea gigas Pacific oyster Canadian Science Publishing Pacific Genome 40 3 397 405 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
description |
Sex and meiosis were studied in induced autotetraploids of the Pacific oyster (Crassostrea gigas Thunberg) and were compared with sex and meiosis in autotriploids and normal diploids. Tetraploid oysters reached sexual maturity at 1 year of age in an approximately 1:1 sex ratio. In contrast with the abnormally high frequency of hermaphrodites among triploids, tetraploids had about the same level of hermaphrodites as normal diploids. Fecundity of tetraploids was comparable to that of normal diploids, differing from the greatly reduced fecundity of triploids. Homologous chromosomes synapsed predominantly as trivalents in eggs from triploids and as quadrivalents in eggs from tetraploids. After fertilization, eggs from tetraploids and triploids went through two meiotic divisions, as normal eggs did. The average gamete chromosome number was 10.0 for diploids and 19.9 for tetraploids. The distribution of gamete chromosome numbers from triploids suggested that the extra chromosome in the trivalent segregated randomly during anaphase I. In tetraploids, however, the two extra chromosomes in the quadrivalents did not segregate independently and, instead, they preferentially cosegregated to opposite poles producing balanced gametes. These results suggest that mechanisms may exist to weigh, balance, and equally distribute quadrivalents, possibly through mitotic force and tension. Errors in chromosome balancing in normal meiosis may result in nondisjunction, which is the primary cause of human aneuploidy.Key words: sex, meiosis, multivalent segregation, polyploidy, aneuploidy, Crassostrea gigas. |
format |
Article in Journal/Newspaper |
author |
Guo, Ximing Allen Jr., Standish K. |
spellingShingle |
Guo, Ximing Allen Jr., Standish K. Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
author_facet |
Guo, Ximing Allen Jr., Standish K. |
author_sort |
Guo, Ximing |
title |
Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
title_short |
Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
title_full |
Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
title_fullStr |
Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
title_full_unstemmed |
Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg) |
title_sort |
sex and meiosis in autotetraploid pacific oyster, crassostrea gigas (thunberg) |
publisher |
Canadian Science Publishing |
publishDate |
1997 |
url |
http://dx.doi.org/10.1139/g97-053 http://www.nrcresearchpress.com/doi/pdf/10.1139/g97-053 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Crassostrea gigas Pacific oyster |
genre_facet |
Crassostrea gigas Pacific oyster |
op_source |
Genome volume 40, issue 3, page 397-405 ISSN 0831-2796 1480-3321 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/g97-053 |
container_title |
Genome |
container_volume |
40 |
container_issue |
3 |
container_start_page |
397 |
op_container_end_page |
405 |
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1809906473144156160 |