虎纹蛙的染色体组型

THE KARYOTYPE OF RANA TIGRINA RUGULOSA WIEGMANN

目的：染色体组型具有物种的特异性，它们在遗传过程中是相对稳定的，研究各种动物的染色体组型，其染色体数目、形态等特征可作为鉴定动物种类的指标。方法：以虎纹蛙（ＲａｎａｔｉｇｒｉｎａｒｕｇｕｌｏｓａＷｉｅｇｍａｎｎ）的骨髓和精巢为材料，制备了虎纹蛙骨髓细胞染色体及精巢生殖细胞减数分裂染色体标本，选择形态完好的中期分裂相进行拍照放大，用常规统计方法测量染色体的相对长度、臂比和着丝粒指数等。结果：虎纹蛙体细胞染色体数２ｎ＝２６，ＮＦ＝５２，可配成１３对同源染色体，其中５对（Ｎｏｓ．１～５）为大型染色体；８对（Ｎｏｓ．６～１３）为小型染色体。全套染色体可分为Ａ组（Ｎｏ．１）、Ｂ组（Ｎｏｓ，２～５）和Ｃ组（Ｎｏｓ．６～１３）。在Ｎｏ．６的长臂远端区域可见次缢痕。同时精母细胞减数分裂中期Ⅱ显示具有１３个二价体，与体细胞染色体对数相符。结论：该蛙染色体的类型。

Objective:There are specificities of the species in the karyotype,which keeps the relative stability in the inheritable process.Therefore,it is an index for identifing the kinds of animals by identifing the karyotype,the number,the pattern of the chromosome and so on.Methods:The chromosomal samples of marrow cell and spermary germinal cell from Rana tigrina rugulosa Wiegmann are made.The metaphase figure of divided cells is chosen and have photographs taken.The relative length,the arm ratio,the centromere index of chromosome and so on are measured by the way of biometrics.Results: The chromosomal number was 2n=26,NF=52 in the body cell of Rana tigrina rugulosa Wiegmann.They were composed of 13 pairs of homologous chromosome,including 5 pairs of large chromosome and 8 pairs of small ones.In those chromosomes,A,B and C groups (No.1,Nos 2￣5,Nos 6￣13 respectively)were identified.In addition,the secondary constriction was found at the distal end of long arm of No.6 chromosome.Thivteen bivalents were showed in the meiotics metaphase Ⅱ of speratocytes,and they accorded with the chromosome pairing of body cell.Conclusion:The type of chromosome and the distribution of secondary constiction in the Rana tigrina rugulosa Wiegmann are an important marker to distinguish the subspecies and the other kinds of frogs.