三角帆蚌(Hyriopsis cumingii)核型分析

RESEARCH ON CHROMOSOMES OF HYRIPOSIS CUMINGII

以三角帆蚌为实验材料 ,采用改进的蚌类染色体制备方法 ,对得到的大量有丝分裂染色体进行排列、测量、分组和C 显带 .结果发现 ( 1 )三角帆蚌有 1 9对共 3 8条染色体 ,可划分为A ,B两组 ;A组包括No .1～No .1 2共 1 2对中着丝粒染色体 ,B组包括No .1 3～No .1 9共 7对染色体 ,由 5对亚中着丝粒染色体 (No .1 4 ,1 5,1 7,1 8,1 9)和 2对亚端着丝粒染色体 (No .1 3 ,1 6)组成 ;( 2 )C 显带结果表明 ,三角帆蚌结构异染色质稀少 ,主要分布在着丝粒区的长、短臂端部或近端部 ;( 3 )No .6号染色体的着丝粒C带以及No .7号染色体短臂末端的端粒C带是三角帆蚌的C 显带的特征性带纹 .

In order to study the chromosome of Hyriposis cumingii, the authors use improved methods by which a lot of mitotic metaphases have been prepared from it’s gonads. After karyotype analysis, the authors find that 1. the number of Hyriposis cumingii chromosomes is 38 (19 pairs) ;2. the karyotype (2 n =38) consists of metacentric (pairs1,2,3,4,5,6,7,8,9,10,11,12), submetacentric (pairs14,15,17,18,19) and subtelocentric (pairs13 and 16) chromosomes. There is no telocentric chromosome at all. With C banding techniques, the authors can conclude: (1) The result of C binding reveals that Hyriposis cumingii has relatively small amount of the constitutive heterochromotin which is usually located on centromeres and near the end of the two arms; (2) Although the interstitial C bands sometimes can be seen, they are relatively rare and unstable; (3) With comparison to other areas, the telometric C band on the end of the short arm of pairs 7 appears very constant and stable, and it usually appears as a dark stainned dot; (4) The centrometric C bands can be apparently observed on nearly every chromosome, but the centrometric C band on pair6 is the most notable among other areas. Both the telometric C band on pair 7 and the centromeric C band on pair6 are the remarkable characteristics of Hyriposis cumingii C banded karytype.