Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
Mol Phylogenet Evol. 2010 May;55(2):473-87. doi: 10.1016/j.ympev.2010.01.031. Epub 2010 Feb 4.
Here we use nuclear and mitochondrial DNA sequence data, combined with morphometric analyses, to clarify the systematic relationships and taxonomy of two complex species of shrews, Suncus montanus and S. murinus, in Sri Lanka. We find that subspecies of S. murinus, Suncus murinus murinus from Anuaradhapura and S. m. caerulescens from Colombo, show little or no genetic difference in the mitochondrial (cytochrome-b and 16SrRNA) and nuclear (Rag 1, aldolase C and EF-1 alpha intron) genes, confirming their classification as a single species. However, two populations of S. murinus from Peradeniya and Udawalawe are identified as putative hybrids of S. murinus and S. montanus. Shrews collected from Peradeniya are best described as a population of S. murinus, but could be identified as S.m. kandianus using morphological features. Nuclear DNA sequence data places this population in a clade with other S. murinus, but mtDNA sequences of the population nests within a clade of S. montanus haplotypes. This discordant pattern of nuclear and mitochondrial genes suggests either hybridization between S. murinus and S. montanus or introgression of S. montanus mitochondrial DNA into S. m. kandianus. S. m. murinus from Udawalawe, which shows no distinct morphological difference from S. m. murinus from Anuradhapura, falls in the clade of S. murinus in both nuclear and mitochondrial trees. In the nuclear gene tree however, S. m.murinus from Udawalawe is placed as a sister taxon to the clade including other S. murinus. Rag 1 gene sequences in Udawalawe individuals suggest recombination of S. murinus and S. montanus DNA within the gene. However, additional nuclear genes are necessary to study the extent of the hybridization of S. murinus and S. montanus.
在这里，我们使用核和线粒体 DNA 序列数据，结合形态计量分析，来阐明斯里兰卡两种复杂的鼩鼱属物种——蒙塔纳斯鼩鼱（Suncus montanus）和坎迪亚纳斯鼩鼱（S. murinus）的系统关系和分类。我们发现，来自阿努拉达普拉的坎迪亚纳斯鼩鼱亚种——S. m. murinus 和来自科伦坡的 S. m. caerulescens，在线粒体（细胞色素-b 和 16SrRNA）和核（Rag 1、醛缩酶 C 和 EF-1α内含子）基因中显示出很小或没有遗传差异，证实了它们被分类为一个单一的物种。然而，来自佩拉德尼亚和乌达瓦拉维的两个 S. murinus 种群被鉴定为 S. murinus 和 S. montanus 的可能杂种。从佩拉德尼亚收集的鼩鼱最好被描述为 S. murinus 的一个种群，但可以通过形态特征将其鉴定为 S.m. kandianus。该种群的核 DNA 序列数据将其置于与其他 S. murinus 聚类中，但该种群的 mtDNA 序列嵌套在 S. montanus 单倍型的聚类中。这种核和线粒体基因的不一致模式表明，S. murinus 和 S. montanus 之间发生了杂交，或者 S. montanus 的线粒体 DNA 已经渗入到 S. m. kandianus 中。来自乌达瓦拉维的 S. m. murinus 与来自阿努拉达普拉的 S. m. murinus 没有明显的形态差异，在核和线粒体树中都属于 S. murinus 聚类。然而，在核基因树中，乌达瓦拉维的 S. m.murinus 被放置在包括其他 S. murinus 的聚类的姐妹分类群中。乌达瓦拉维个体的 Rag 1 基因序列表明，S. murinus 和 S. montanus 的 DNA 在基因内发生了重组。然而，需要额外的核基因来研究 S. murinus 和 S. montanus 杂交的程度。
