Tan A M
Hawaiian Evolutionary Biology Program, Pacific Biomedical Research Center, University of Hawaii at Manoa, Honolulu 96822.
Chromosome Res. 1994 Jul;2(4):281-92. doi: 10.1007/BF01552722.
Chromosomal variation was analysed in 22 populations of newts of the salmandrid genus Taricha of western North America, and compared with that of the eastern North American newts of the genus Notophthalmus. The karyotypes of the species Taricha and Notophthalmus were very similar. However, there was considerable variation in the distribution patterns of heterochromatins (revealed by C-banding) and in the sites of the nucleolar organizing region (NOR) (revealed by fluorochrome chromomycin A3 banding) within and between species of these two genera. Chromosomal variation patterns were interpreted in relation to a phylogenetic hypothesis derived from data on mitochondrial DNA sequences and allozyme variation. This study suggests that the pattern distributions of heterochromatins in chromosomes of Taricha are more derived than those of its sister taxon Notophthalmus. Furthermore, the chromosomal NOR types found in the southernmost and northernmost populations of T. granulosa, in the northernmost populations of T. t. sierrae, and in the southern populations of T. t. torosa are recently derived. The implications of this chromosomal variation for phylogeny and biogeography are discussed.
对北美西部无肺螈科肥螈属22个种群的蝾螈染色体变异进行了分析，并与北美东部眼斑螈属蝾螈的染色体变异进行了比较。肥螈属和眼斑螈属物种的核型非常相似。然而，在这两个属的物种内部和物种之间，异染色质的分布模式（通过C带显示）以及核仁组织区（NOR）的位置（通过荧光色素放线菌素A3带显示）存在相当大的差异。根据从线粒体DNA序列和等位酶变异数据得出的系统发育假说，对染色体变异模式进行了解释。这项研究表明，肥螈染色体中的异染色质模式分布比其姐妹分类单元眼斑螈的更为衍生。此外，在粗皮肥螈最南端和最北端的种群、加州肥螈最北端的种群以及虎斑肥螈南部的种群中发现的染色体NOR类型是最近衍生出来的。讨论了这种染色体变异对系统发育和生物地理学的影响。
