小荚蛏的核型分析

The preliminary study on karyotype of Siliqua minimai Gmelin

以小荚蛏(Siliqua minimai Gmelin)担轮幼虫为材料,采用热滴片法进行染色体制备和核型分析。结果表明,小荚蛏二倍体染色体数目为2n=38,核型公式为2n=12m+14sm+10st+2t,染色体臂数(NF)=64,未发现性染色体和随体。与已经研究的大竹蛏、缢蛏和长竹蛏相比,小荚蛏核型更不对称,st/t类型数量更多,推测小荚蛏较为原始。用类平均法对它们进行聚类分析,结果小荚蛏与它们的亲缘关系最远。

The karytype ofSiliqua minimai was studied on its trochophore by means of hot-dropping method. The diploid chromosome number ofS. minimai is 2n=38 and the karytype can be described by 12m＋14sm＋10st＋2t with NF=64. The sex chromosomes and the satellites were not found. Compared with Solen grandis, Sinonovacula constricta and Solen strictus, the karyotype of S. minimai is more dissymmetrical and subtelocentric（st） and telocentric（t） type of chromosome number, so it was suggested that S. minimai is more primitive. The clustering analysis was made by group mean method among them and the result showed that there was the farthest relationship between S. minimai and other species.