平鲷不同发育类型的染色体核型分析

Studies on chromosome karyotypes of different developments of Rhabdosargus sarba

研究了平鲷(Rhabdosargus sarba)自然群体和人工诱导雌核发育的染色体核型,结果表明:平鲷自然群体和雌核发育二倍体的染色体没有明显的形态结构差异,数目均为2n=48,中部着丝点染色体2对,亚中部着丝点染色体1对,亚端部着丝点染色体2对,端部着丝点染色体19对,其核型公式为4m+2sm+4st+38t,染色体总臂数(NF)54,染色体上未见随体、次缢痕,也未发现有明显异形的性染色体;雌核发育单倍体染色体数目n=24,中部着丝点染色体有2条,亚中部着丝点染色体1条,亚端部着丝点染色体2条,端部着丝点染色体19条,核型公式为2m+1sm+2st+19t,染色体总臂数(NF)27,单倍体染色体数量是其二倍体染色体的一半,其形态和结构与同源的另一套染色体相似.根据鲷科几种主要鱼类的核型,结合它们之间的杂交后代的性状表现和遗传亲和力、个体发育及其基本生物学特征分析,在分类学上平鲷可以归入鲷属,与黑鲷(Sparus macrocephalus)和黄鳍鲷(Sparus latus)同为一属.

The karyotypes of the different developmental types of silver sea bream, Rhabdosargus sarba were analyzed. The result indicated that the chromosome numbers of both natural silver sea bream and artificial-induced gynogenetic diploid are 2n = 48, which they have similar chromosomal shape and structure with 2 pairs of metacentrics, 1 pairs of submetacentrics, 2 pairs of acrocentrics and 19 pairs of telocentrics, without special-shaped sex chromosomes. Their karyotype formulas are 4m ＋ 2sin ＋ 4st ＋ 38t, and arm numbers（NF） are 54. The chromosome numbers of gynogenetic haploid are 24, which karyotype formula is 2m ＋ lsm ＋ 2st ＋ 19t and its arm numbers （NF） are 27. The chromosomal shape and structure of gynogenetic haploid is accordance with a set of chromosome of diploid. Comparing silver sea bream with several species of Sparidea fishes by the karyotype, the phenotype, individual development and the elementary biological characters of their filial generation, silver sea bream, Rhabdosargus sarba can be classified into Sparus genus with Sparus macrocephalus and Sparus latus.