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Demonstration of a WART in a hybrid zone of the common shrew (Sorex araneus Linnaeus, 1758)

Pavlova S.V., Kolomiets O.L., Bulatova N.Sh., Searle J.B.

Abstract. Among common shrews from the hybrid zone between the Moscow and Seliger chromosomal races, we found an adult male characterised by two metacentrics not found in either race (hm, nq). These metacentrics apparently arose by a whole-arm reciprocal translocation (WART) of two of the Seliger metacentrics (hn, mq). Although such rearrangements have been postulated previously to explain racial differences, this is the first direct evidence of a WART in the common shrew. Apart from the unusual metacentrics, the karyotype of the male shrew was that of an F1 hybrid, i.e. this individual was a complex heterozygote that formed a chain-of-11 configuration at meiosis. Regular synapsis was demonstrated at pachytene, complete configurations were scored at diakinesis, and mature sperm were observed within the meiotic preparations.