GENETIC DIFFERENTIATION AND ZOOGEOGRAPHY OF ASIAN SUNCUS-MURINUS (MAMMALIA, SORICIDAE)

Protein electrophoresis was used to assess the phylogenetic relationsh ips of populations of the phenotypically variable Asian house shrew Su ncus murinus. These populations represent a sample of both commensal a nd wild forms. They were compared to another taxon, S. montanus, which was formerly considered conspecific with S. murinus. Suncus dayi was used as an outgroup in all phylogenetic reconstructions. Within the S. murinus lineage, the allozyme data show very low levels of genetic di fferentiation among both wild and commensal Southeast Asian and Japane se samples when compared to the Indian populations. This pattern is co nsistent with the classical hypothesis of a recent introduction by man in Eastern Asia. The higher genetic diversity found within S. murinus from India, as well as previous mitochondrial and karyological result s suggest that this area is the probable centre of origin for the spec ies. Although the lack of gene flow between S. murinus and S. montanus is clearly established in an area of sympatry in Southern India, one Asian house shrew sampled in Nepal was more closely related to S. mont anus. This could either reflect the retention of an ancestral polymorp hism, or result from a hybridization episode between S. murinus and S. montanus. Similar conclusions were also suggested in mitochondrial DN A studies dealing with animals sampled in the Northern parts of the In dian subcontinent. Clearly, further data on Suncus from this area are needed in order to assess these hypotheses. (C) 1995 The Linnean Socie ty of London