不同地理区域鲫鱼染色体银染核仁组织者的比较研究

本文对不同地理区域的鲫鱼(Carassius auratus)—滇池高背鲫、低背鲫、方正银鲫(C.auratusgibelio)的核型及核仁组织者NORs进行了比较研究,并对高背鲫来源作些初步探讨,结果如下: 1.低背鲫Carassius auratus (back low type):2n=100,22m+30sm+48t.st,NORs=4,出现于第5—6对亚中着丝粒染色体短臂。 2.滇池高背鲫Carassius auratus(back high type):2n=156,30m+46sm+80t.st,NORs=6,出现于第5—7对亚中着丝粒染色体短臂。 3.方正银鲫C.auratus gibelio:2n=162,32m+52sm+78t.st NORs=4,出现于第5—6对亚中着粒染色体短臂。

A COMPARATIVE STUDY OF THE AG-NORS OF CARASSIUS AURATUS FROM DIFFERENT GEOGRAPHIC DISTRICTS

The karyotype and the silver stained nucleolus organizer regions of Caras-sius auratus from different geographic districts were studied.In Carassius auratus (back-low type), there are 22 metacentric chromosomes, 30 submetacentric and 48 telocentric or subtelocentric (2n = 100), NORs = 4. No marker chromosome was found in C. auratus (back-low type).The chromosome number of the back-high type of Carassius auratus is 156. The karyotype formula is 30m+ 46sm+80t, st. There is one pair of chromosomes showing secondary constriction on the short arm of Nos. 6 submetacentric chromosome and 3 pair of NORs on the short arm of Nos. 5, 6, 7, submetacentric.The chromosome number of Carassius auratus gibelio is 162. The karyotype formula is 32m+ 52sm+78t. st, NORs = 4. It also has one pair of chromosomes with secondary constriction on the short arm of Nos. 6 submetacentric. 2 pair of NORs can be found at most of metaphases.