Eldridge M D, Johnston P G, Lowry P S
School of Biological Sciences, Macquarie University, New South Wales, Australia.
Cytogenet Cell Genet. 1992;61(1):34-9. doi: 10.1159/000133365.
G-banded metaphase preparations of cultured fibroblasts were used to construct the karyotypes of Petrogale brachyotis (2n = 18) and P. concinna (2n = 16). The two karyotypes differ significantly from the plesiomorphic karyotype of the genus and from those of all other Petrogale species examined. Petrogale brachyotis and P. concinna are characterised by three synapomorphies: a 1-10 centric fusion, a 3a-6 centric fusion, and a submetacentric chromosome 2 (2s). Both species also possess autapomorphies. Petrogale brachyotis is characterised by submetacentric chromosomes 5 (5s) and 4 (4sm), whereas P. concinna is characterised by a 5-9 centric fusion and a submetacentric chromosome 8 (8m). The 2s, 5s, 4sm, and 8m chromosomes all appear to be derived from their plesiomorphic homologs by centromeric transpositions. Although the rate of chromosome evolution varies considerably in Petrogale, the genus clearly exhibits karyotypic orthoselection, with all the autosomal rearrangements identified being either centric fusions or centromeric transpositions. This study also illustrates the potential for convergent evolution in chromosomally diverse groups and demonstrates the importance of G-banding studies for accurate identification of chromosome rearrangements.
利用培养的成纤维细胞的G带中期制备物构建了短耳岩袋鼠（2n = 18）和秀丽岩袋鼠（2n = 16）的核型。这两种核型与该属的原始核型以及所有其他已检测的岩袋鼠物种的核型均有显著差异。短耳岩袋鼠和秀丽岩袋鼠具有三个共同衍征：一个1 - 10着丝粒融合、一个3a - 6着丝粒融合以及一条亚中着丝粒染色体2（2s）。这两个物种也都具有自身衍征。短耳岩袋鼠的特征是亚中着丝粒染色体5（5s）和4（4sm），而秀丽岩袋鼠的特征是一个5 - 9着丝粒融合和一条亚中着丝粒染色体8（8m）。2s、5s、4sm和8m染色体似乎都是通过着丝粒转座从它们的原始同源染色体衍生而来。尽管岩袋鼠属中染色体进化速率差异很大，但该属明显表现出核型定向选择，所有已确定的常染色体重排均为着丝粒融合或着丝粒转座。这项研究还说明了染色体多样化群体中趋同进化的可能性，并证明了G带研究对于准确识别染色体重排的重要性。
