宽体沙鳅的染色体核型与DNA含量分析

为了解宽体沙鳅(Sinibotia reevesae)的种质特征,以野生宽体沙鳅为材料,采用腹腔注射植物血球凝集素(PHA)和秋水仙素,肾组织细胞短期培养、常规空气干燥法制备染色体标本,并对其核型进行分析。以鸡(Gallus gallus)血细胞DNA含量(2.50 pg/2c,2c指二倍体)为标准,用流式细胞仪测定宽体沙鳅外周血细胞的DNA含量。结果表明:(1)宽体沙鳅的染色体数目为2n=96,核型组成公式为2n=36m+14sm+20st+26t,染色体总臂数NF=146;未发现与性别相关的异型染色体。(2)宽体沙鳅的DNA含量为(2.60±0.36)pg/2c。通过与其他26种鳅科鱼类核型进行比较,发现宽体沙鳅属于鳅科鱼类中的特化类群,其染色体核型经历了罗伯逊易位和染色体多倍化等过程。本研究结果可为宽体沙鳅种质资源保护和细胞遗传学研究提供基础资料。

Chromosome Karyotype and DNA Content of Sinibotia reevesae

In order to investigate the cytogenetic characters of Sinibotia reevesae,the chromosome number and karyotype of S.reevesae were analyzed using a routine method including intraperitoneal injection of PHA and colchicine,nephrocyte cultivation in vivo,and slides preparation with air—drying.Erythrocyte nuclear DNA content of S.reevesae was determined by using a flow cytometer (BD Accuri TM C6) with the chicken erythrocytes (their DNA content is 2.50 pg) serving as reference cells.The results showed that S.reevesae was diploid,the chromosome number was 2n =96,and the karyotype formula was 2n =36m + 14sm + 20st + 26t,and arms number (NF) was 146 (Table 2 and Fig.1).The heterosomes were not observed.The DNA content of S.reevesae was 2.60 ± 0.36 pg/2c (n =10,Fig.2).By comparing with the chromosome karyotypes of other 26 Cobitidae species,it was concluded that S.reevesae should belong to specialization group,and karyotype of S.reevesae might evolve from the type of Cobitidae ancestors by Robertsonian translocation of chromosomes and chromosome polyploidy.Our results could provide essential data for broodstock conservation and cytogenetic research of the S.reevesae.