中国五种锄足蟾科无尾两栖动物的细胞遗传学研究

THE CYTOGENETIC STUDY ON FIVE PELOTOID SPECIES OF ANURA IN CHINA

本文对中国５种锄足赡科无尾两栖动物的骨髓细胞有丝分裂中期作了细胞遗传学研究，内容包括核型、Ａｇ－ＮＯＲｓ和Ｃ－带。研究结果表明景东角蟾：Ｚｎ＝２６（２０Ｍ＋４ＳＭ＋２ＳＴ），５＋８，ＳＣ和Ａｇ－ＮＯＲｓ位于６ｐ（ｐｅｒ），同时呈Ｃ－带正染。Ｃ－带以着丝点区域正染为主；粗皮角蟾：Ｚｎ＝２６（２０Ｍ＋６ＳＭ），５＋８，Ａｇ－ＮＯＲｓ在６ｑ（ｉｎｔｅｒ），以着丝点Ｃ－带为主，但Ｎｏｓ．１２，１３有明显的端位Ｃ－带；小口拟角蟾：Ｚｎ＝２６（２４Ｍ＋ＺＳＭ），６＋７，ＳＣ和Ａｇ－ＮＯＲｓ位于５ｐ（ｉｎｔｅｒ），有十分发达的着丝点Ｃ－带；利川齿蟾：Ｚｎ＝２６（２２Ｍ＋４ＳＭ），６＋７，ＳＣ和Ａｇ－ＮＯＲｓ位于时６ｑ（ｉｎｔｅｒ），以着丝点Ｃ－带为主；沙巴拟髭蟾：２ｎ＝２６（２２Ｍ＋４ＳＭ），６＋７，ＳＣ和Ａｇ－ＮＯＲｓ位于６ｑ（ｉｎｔｅｒ），着丝点Ｃ－带为主，有明显的染色体数目变异。有雌雄二性个体做实验的３个种均未发现异形性染色体。

The cytogenetic study on the karyotypes,Ag-NORs,C-banding and other features on five pelobatoid toad species in China had been made using the method of vapour fixation of mitosis metaphase of the marrow cells.The results showed that Megophrys jingdongensis have 2n=26(20M+4SM+2ST),5+8,SC and Ag-NORs localized on 6pper at which C-positive staining also. The centromeric C-bands dominated.M.palpebralispinosa 2n= 26(20M+6SM, 5+8, 6qinter is distinct Ag-staining.Except for Nos.12,13,which has obvious terminal C-staining,all the chromosomes presented centromeric C-bands.Ophryphyne microstoma 2n=26(24M+2SM),6+7,SC and Ag-NORs are on 5pinter.Specially there are quite developed C-bands on all the centromeric regions.Oreolalax lichuanensis 2n=26(22M+4SM),6+7,SC and Ag-NORs located on 6qinter Leptobrachium chapeensis 2n=26(22M+4SM), 6+7,same location of Ag-NORs and C-bands with the former species it has,the varied chromosomes(26,27,28)occured,but the exceed chromosomes are without C-staining.No heteromorphic chromosomes related to the sexuality were found in three species with both sexes.