Suzuki H, Hosoda T, Sakurai S, Tsuchiya K, Munechika I, Korablev V P
Division of Molecular Genetics, Jikei University School of Medicine, Tokyo, Japan.
Jpn J Genet. 1994 Aug;69(4):397-406. doi: 10.1266/jjg.69.397.
We analyzed the restriction fragment length polymorphisms in the spacer regions of ribosomal DNA (rDNA), using twelve restriction enzymes, to examine whether the Iriomote cat is related to the leopard cat (Felis bengalensis). A restriction map for each taxon was constructed and the major taxon-specific types of repeating unit (repetypes) were characterized on the basis of the arrangements of restriction sites. The Iriomote cat and the leopard cat share a common repetype but this repetype is different from that of the domestic cat (F. catus) with an estimated sequence divergence of 1.5% and from that of the ocelot (F. paradalis) with an estimated sequence divergence of 2.5%. These results indicate that, phylogenetically, the Iriomote cat is closely related to the leopard cat and that the ancestral population moved from the continent to Iriomote Island quite recently. The rDNA arrays of the leopard cat exhibit considerable intragenomic size-variation, which is thought to have emerged as a result of differences in numbers of repeated DNA segments, whereas the extent of such size-variation is much lower in the rDNA of the Iriomote cat. It appears that, even though migration of the Iriomote cat occurred relatively recently, the population has diverged to some extent from its continental counterpart, perhaps via fixation of preexistent intraspecific variations rather than by generation of new variations.
我们使用12种限制性内切酶分析了核糖体DNA（rDNA）间隔区的限制性片段长度多态性，以研究西表猫是否与豹猫（豹猫属孟加拉种）有关。构建了每个分类单元的限制性图谱，并根据限制性位点的排列对主要的分类单元特异性重复单元类型（重复型）进行了表征。西表猫和豹猫共享一种共同的重复型，但这种重复型与家猫（家猫）的不同，估计序列差异为1.5%，与豹猫（豹猫属南美草原种）的不同，估计序列差异为2.5%。这些结果表明，在系统发育上，西表猫与豹猫密切相关，并且其祖先种群最近才从大陆迁移到西表岛。豹猫的rDNA阵列表现出相当大的基因组内大小变异，这被认为是由于重复DNA片段数量的差异而出现的，而西表猫的rDNA中这种大小变异的程度要低得多。看来，尽管西表猫的迁移发生得相对较近，但该种群可能通过固定已有的种内变异而非产生新变异，在一定程度上与其大陆同类种群产生了分化。
