Robertsonian chromosomal variation in the house musk shrew (Suncus murinus, Insectivora: Soricidae) and the colonization history of the species

Abstract

A high-resolution G-banding technique was used to identify five metacentrics that characterize Suncus murinus from Sri Lanka. These metacentrics were shown to be the product of Robertsonian fusion of acrocentric chromosomes identical to those in the standard karyotype defined by M.B. Rogatcheva et al. Two of the metacentrics in the Sri Lankan shrews (Rb(10.12) and Rb(14.15)) were the same as those reported by C.H. Sam et al. in Malayan populations of S. murinus. This finding provides strong support for the suggestion of T.H. Yosida that metacentric-carrying shrews colonized Malaya from Sri Lanka and hybridized with individuals of standard karyotype, generating the Robertsonian polymorphism now observed. In addition to the Robertsonian variation in S. murinus, we have used our high resolution technique (G- and C-banding) to characterize variants on chromosome 7, the X chromosome, and the Y chromosome.Key words: chromosome variation, Robertsonian fusions, colonization history, shrew, Suncus murinus.