Tymowska J
Cytogenet Cell Genet. 1977;18(4):165-82. doi: 10.1159/000130761.
A comparative study of the karyotypes of eight Xenopus species and subspecies possessing a diploid number of 36 chromosomes (X.l. laevis, X.l. petersi, X.l. victorianus, X. borealis, X. gilli, X. fraseri, and X. clivii) was performed. Karyotypes based on the morphology and size of chromosomes differ only by the type and position of secondary constrictions. Some of these constrictions are nucleolar organizers, recognizable by mitotic chromosomal association. By comparing the chromosomes bearing secondary constrictions, an attempt is made to establish the cytotaxonomic relationships. The close relationship between the subspecies X.l. laevis, X.l. petersi, and X.l. victorianus is confirmed; X. borealis, however, is a separate species much nearer to X. muelleri. The karyotype of X. gilli is interpreted as being intermediate to these two groups. X. clivii could be regarded as a species close to the group of X. muelleri. X. fraseri, having a particular type of secondary constriction, is systematically more distant.+20
对8种二倍体染色体数为36条的非洲爪蟾物种和亚种（光滑爪蟾指名亚种、彼得斯光滑爪蟾、维多利亚光滑爪蟾、北方爪蟾、吉利爪蟾、弗雷泽爪蟾和克利夫爪蟾）的核型进行了比较研究。基于染色体形态和大小的核型仅在次缢痕的类型和位置上有所不同。其中一些缢痕是核仁组织区，可通过有丝分裂染色体联会识别。通过比较带有次缢痕的染色体，试图建立细胞分类学关系。光滑爪蟾指名亚种、彼得斯光滑爪蟾和维多利亚光滑爪蟾这几个亚种之间的密切关系得到了证实；然而，北方爪蟾是一个独立的物种，与穆勒爪蟾更为接近。吉利爪蟾的核型被解释为介于这两组之间。克利夫爪蟾可被视为与穆勒爪蟾组接近的一个物种。弗雷泽爪蟾具有一种特殊类型的次缢痕，在系统发育上距离更远。
