花背蟾蜍和中华大蟾蜍胚胎染色体组型分析

本研究用空气干燥制片法,以胚胎细胞为材料,对花背蟾蜍和中华大蟾蜍从囊胚期到尾芽期胚胎染色体的组型及其变化进行了比较分析。结果表明:两种蟾蜍发育各期的胚胎染色体均与其成体有基本相同的染色体组型。染色体绝对长度由囊胚列原肠晚期逐渐增长,神经胚期开始下降,尾芽期显著缩短。囊胚期染色体数目大多为四倍体。四倍体的出现率随发育时期的进展而逐渐减少,到神经胚期恢复正常。囊胚期分裂相中有额外随体,其出现率在不同染色体及其长、短臂上均无一定的规律。

Analyses of the Embryonic Chromosomes of Bufo Bufo Gargarizans and Bufo Raddei

The karyotypes of Bufo bufo gargarizans and Bufo raddei embryos and their changes during the early development from blastula to tail-bud embryos are studied with embryonic cells by air-dried method. The results indicated that the embryonic karyotypes of the two species in various early stages are similar to those of their adults respectively. The chromosome length increases gradually as the embryos proceed from blastulae to late gastrulae, but begin to reduce in neurulae and drastically shorten in tail-bud embryos. Tetraploid karyotype is the majority in blastula and reduces gradually as the development proceeds. In neurulae, all change to the diploid karyotype. Extra satellite appears randomly in the long or short arms of the metaphase chromosomes of blastulae.