A Preliminary Study of Chromosomes of Two Species of Oysters (Ostrea lurida and Crassostrea gigas)

1967 ◽  
Vol 24 (10) ◽  
pp. 2155-2159 ◽  
Author(s):  
Muzammil Ahmed ◽  
Albert K. Sparks
Keyword(s):  
Chromosome Number ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Diploid Chromosome Number ◽  
Ostrea Lurida ◽  
Lampbrush Chromosomes ◽  
Somatic Metaphase ◽  
The Pacific ◽  
Preliminary Study ◽  
Native Oyster

A diploid chromosome number of 20 (n = 10) was found for each of the native oyster Ostrea lurida, and the Pacific oyster Crassostrea gigas. The diploid complements of the native oyster were normal but in the Pacific oyster atypical numbers, polyploid nuclei, and abnormal cleavage was observed in some somatic metaphase plates. The diplotene meiotic bivalents of the native oyster resembled lampbrush chromosomes.

Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg)

Genome ◽  
1997 ◽  
Vol 40 (3) ◽  
pp. 397-405 ◽  
Author(s):  
Ximing Guo ◽  
Standish K. Allen Jr.
Keyword(s):  
Chromosome Number ◽  
Sex Ratio ◽  
Crassostrea Gigas ◽  
High Frequency ◽  
Sexual Maturity ◽  
Pacific Oyster ◽  
Extra Chromosome ◽  
Homologous Chromosomes ◽  
The Pacific ◽  
Normal Meiosis

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.

Combined effects of pollutants and salinity on embryo-larval development of the Pacific oyster, Crassostrea gigas

2016 ◽  
Vol 113 ◽  
pp. 31-38 ◽  
Author(s):  
Perrine Gamain ◽  
Patrice Gonzalez ◽  
Jérôme Cachot ◽  
Patrick Pardon ◽  
Nathalie Tapie ◽  
...  
Keyword(s):  
Larval Development ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Combined Effects ◽  
The Pacific

Differentially methylated gene regions between resistant and susceptible heat-phenotypes of the Pacific oyster Crassostrea gigas

Aquaculture ◽  
2021 ◽  
pp. 736923
Author(s):  
Roberto Arredondo-Espinoza ◽  
Ana M. Ibarra ◽  
Steven B. Roberts ◽  
Maria Teresa Sicard-Gonzalez ◽  
Cristina Escobedo-Fregoso
Keyword(s):  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
The Pacific ◽  
Differentially Methylated Gene

Genetic Determinants of Protandric Sex in the Pacific Oyster, Crassostrea gigas Thunberg

Evolution ◽  
1998 ◽  
Vol 52 (2) ◽  
pp. 394 ◽  
Author(s):  
Ximing Guo ◽  
Dennis Hedgecock ◽  
William K. Hershberger ◽  
Kenneth Cooper ◽  
Standish K. Allen
Keyword(s):  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Genetic Determinants ◽  
The Pacific
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