扁圆吻鲴形态特征及生化遗传特性分析

Morphological and Biochemical Genetic Characteristics of Distoechodon compressus

[目的]从形态特征、染色体核型和乳酸脱氢酶3个层面评估扁圆吻鲴种质资源状况,为丰富鲴亚科鱼类的遗传特性资料,种质评估、种质保护及利用提供理论参考。[方法]采用传统的形态学测量方法对60尾扁圆吻鲴的生物学性状进行描述,采用植物血球凝集素(PHA)和秋水仙素腹腔注射肾细胞直接制片法及同工酶电泳等分子生物学方法,开展扁圆吻鲴的细胞遗传特性及生化遗传特性研究。[结果]扁圆吻鲴体长形,侧扁,腹部圆,肛门前方无腹棱。头小,吻突出。口下位,横裂,下颌有很发达的角质缘。鳃耙短且扁薄,排列很紧密。鳞小,体背部深黑色,腹部银白。背、尾鳍灰黄色,尾鳍边缘黑色,偶鳍基部黄色。鳔分二室,且后室较前室大,前室钝圆,后室末端稍尖且呈锥状;扁圆吻鲴的可数性状依次为背鳍鳍式(D.Ⅲ,6~8)、臀鳍鳍式(A.Ⅱ,6~9)、侧线鳞数(76~89)、鳃耙数(94~103);其体细胞染色体数为2n=48,核型公式为18m+18sm+8st+4t,臂数(NF)为84;其不同采样点的样本眼睛晶状体乳酸脱氢酶(LDH)均有5条同工酶谱带,由Ldh-A、Ldh-B两个基因编码。[结论]该研究中扁圆吻鲴的形态特征与已报道的鲴亚科鱼类形态特征存在一定的差异,而体细胞染色体数、核型以及乳酸脱氢酶的表达均与其他鲴亚科鱼类的特征相一致。

[Objective]To evaluate the germplasm resources of Distoechodon compressus from three aspects of morphological characteristics,chromosome karyotype and lactate dehydrogenase,and provide theoretical basis for the enrichment of genetic characteristics,germplasm evaluation,formulation of germplasm standards,germplasm protection and utilization of D.compressus.[Method]The biological characteristics of 60 heads of D.compressus were described by the traditional morphological measurement method.The cell genetic characteristics and biochemical genetic characteristics of D.compressus were studied by the methods of PHA,colchicine and isozyme electrophoresis.[Result]D.compressus had a long body,flat side,round abdomen and no ventral edge in front of anus.It had a small head with a protruding kiss.Its mouth was located at the lower part of the head.The mandible had very developed horny margin.Gill rakes were short,flat and thin,closely arranged.The back of the body was dark black covered with small scales,and the belly was silvery white.Its dorsal and caudal fins were grayish yellow,the caudal fins had black edges,and the base of the even fins was yellow.The swim bladder was divided into two chambers with the smaller blunt and round of anterior chamber.The posterior chamber end was slightly pointed and cone-shaped.The four countable characters of D.compressus were dorsal fin type(D.Ⅲ,6-8),gluteal fin type(A.Ⅱ,6-9),lateral scales(10-12),gill rake(94-103).The chromosome number of somatic cells was 2n=48,the karyotype formula was 18m+18sm+8st+4t,and the arm number(NF)was 84.LDH of eye crystal at different sampling points had five isozyme bands,which were encoded by two genes of Ldh-A and Ldh-B.[Conclusion]In this study,there were some differences of the morphological characteristics between D.compressus and Xenocyprinae,the number of chromosome,karyotype and expression of LDH in somatic cells are consistent with those of other Xenocyprinae.