Norris T B, Rickards G K, Daugherty C H
School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
Cytogenet Genome Res. 2004;105(1):93-9. doi: 10.1159/000078014.
We examined karyotypes of the endemic New Zealand reptile genus Sphenodon (tuatara) from five populations, finding a karyotype unchanged for at least one million years. Animals karyotyped were from five geographically distinct populations, representing three groups, namely S. guntheri, S. punctatus (Cook Strait group), and S. punctatus (northeastern North Island group). All five populations have a diploid chromosome number of 2n = 36, consisting of 14 pairs of macrochromosomes and four pairs of microchromosomes. Chromosomal differences were not found between the five populations nor between female and male animals, except for one animal with a structural heteromorphism. Similarity between Sphenodon and Testudine karyotypes suggests an ancestral karyotype with a macrochromosome complement of 14 pairs and the ability to accumulate variable numbers of microchromosome pairs. Our research supports molecular phylogenies of the Reptilia.
我们检查了来自五个种群的新西兰特有爬行动物楔齿蜥属（喙头蜥）的核型，发现其核型至少在一百万年内未发生变化。进行核型分析的动物来自五个地理上不同的种群，代表三个类群，即冈氏楔齿蜥、斑点楔齿蜥（库克海峡种群）和斑点楔齿蜥（北岛东北部种群）。所有五个种群的二倍体染色体数均为2n = 36，由14对大染色体和4对小染色体组成。除了一只具有结构异态性的动物外，五个种群之间以及雌雄动物之间均未发现染色体差异。楔齿蜥与龟鳖类核型的相似性表明，其祖先核型具有14对大染色体，并且能够积累数量可变的小染色体对。我们的研究支持了爬行纲的分子系统发育。
