title: Chromosome inheritance in triploid Pacific oyster Crassostrea gigas Thunberg.
abstract: Reproduction and chromosome inheritance in triploid Pacific oyster (Crassostrea gigas Thunberg) were studied in diploid female x triploid male (DT) and reciprocal (TD) crosses. Relative fecundity of triploid females was 13.4% of normal diploids. Cumulative survival from fertilized eggs to spat stage was 0.007% for DT crosses and 0.314% for TD crosses. Chromosome number analysis was conducted on surviving progeny from DT and TD crosses at 1 and 4 years of age. At Year 1, oysters from DT crosses consisted of 15% diploids (2n=20) and 85% aneuploids. In contrast, oysters from TD crosses consisted of 57.2% diploids, 30.9% triploids (3n=30) and only 11.9% aneuploids, suggesting that triploid females produced more euploid gametes and viable progeny than triploid males. Viable aneuploid chromosome numbers included 2n+1, 2n+2, 2n+3, 3n-2 and 3n-1. There was little change over time in the overall frequency of diploids, triploids and aneuploids. Among aneuploids, oysters with 2n+3 and 3n-2 chromosomes were observed at Year 1, but absent at Year 4. Triploid progeny were significantly larger than diploids by 79% in whole body weight and 98% in meat weight at 4 years of age. Aneuploids were significantly smaller than normal diploids. This study suggests that triploid Pacific oyster is not completely sterile and cannot offer complete containment of cultured populations.
authors.affiliation: Experimental Marine Biology Laboratory, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071, PRC.
authors.forename: N
authors.initials: N
authors.lastname: Gong
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: B J
authors.initials: BJ
authors.lastname: Landau
authors.forename: X
authors.initials: X
authors.lastname: Guo
mesh_terms: D000818:Animals; D002875:Chromosomes; D019143:Evolution, Molecular; D005260:Female; D005298:Fertility; D040582:Inheritance Patterns / Q000235:genetics*; D007621:Karyotyping; D008136:Longevity; D008297:Male; D008677:Metaphase; D010125:Ostreidae / Q000235:genetics*; D011123:Polyploidy