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鲫(Carassius auratus)是洞庭湖水系一种重要的经济鱼类。为了解洞庭湖水系野鲫的细胞遗传背景,采用PHA和秋水仙素活体注射法,对沅水和澧水采集的野鲫样本逐一进行肾细胞染色体制片及组型分析。结果发现,在两条河流的野鲫群体中均检测出染色体数为100和基本染色体数为150的两种不同倍性个体,其中,两条河流染色体数为100的二倍体鲫组型公式为2N=28M+22SM+28ST+22T,NF=150;基本染色体数为150的三倍体鲫组型公式为3N=42M+33SM+42ST+33T,NF=225。在沅水和澧水不同采样点随机采集的共100尾野鲫中,检测出的三倍体比例(85%)远高于二倍体(15%),且二倍体与三倍体鲫个体在形态特征上不存在明显差异(P>0.05)。两种不同倍性鲫在同一水体的共存对于鲫的遗传进化与选育具有一定的理论和实践意义,而二倍体鲫种群的大量减少,则提示我们应该从染色体组遗传多样性角度加强对洞庭湖水系二倍体野鲫资源的保护。
Carassius auratus is an economically important fish species in the Dongting Lake water system. In order to understand the cytogenetic background of wild crucian carp in Dongting Lake, PHA and colchicines in vivo injection were used to analyze the chromosomes and genotypes of wild Carassius auratus collected from Yuanshui and Huangshui respectively. The results showed that two different ploidy individuals with 100 chromosomes and 150 basic chromosomes were detected in the wild Carassius auratus populations of two rivers. Among them, the diploid crucian carp type formula with 100 chromosomes in two rivers 3N = 42M + 33SM + 42ST + 33T, NF = 225 for the 2 × 28M + 22SM + 28ST + 22T and NF = 150; Of the 100 wild Carassius auratus collected randomly from different sampling points in Yuanshui and Huangshui, the triploid percentage (85%) was much higher than that of diploid (15%), and the diploid and triploid crucian There was no significant difference in morphological characteristics (P> 0.05). The coexistence of two different ploys in the same water body has certain theoretical and practical significance for the genetic evolution and selection of the crucian carp. However, the large decrease of the diploid crucian carp population suggests that we should strengthen the genetic diversity of the crucian carp Conservation of diploid Carassius auratus in Dongting Lake water system.