Genetic differentiation of house mice in the fauna of the former U.S.S.R.: results of cytogenetic studies

Abstract

A cytogcnic study of nearly 200 h o u r niicc (.\fits I T I I~. W U~U Jsensu Jtrirto) and aboriginal mice (Afu hor/rtlnnir.s, .2fus abbotti) of the subgrnus , l f i t~ was carried out. Mice were sampled from most localitics in the fornirr U.S.S.R.. from thr western borders to the Far East, and it was shown that i t is possible to usr eytogenrtic markrrs to classify the apecies and rarr subspecies of the suhgenus. Surh markers included the characteristic morphology or the sex chromosomes and the pattrrn of distribution of the C:-heterochromatiri in thr karyotype. Thus. the abori+nal mice, togrther with M . sprdits, arr characterized by a significant reduction in the size of the Y chrornosomr. In addition, the variant of the X chrornosomr (so called 'mulosrinu' type) previously only observed in Japanese ,\I. m. moloJJinu was found in all the A~U J musrulus sampled from thc fauna of the former U.S.S.R. Another type, the so called 'doms/tcuJ', is a plcsiomorphic variant of' the S chromosome which is normally found in .21. domrstim. .\f. h i n t~l n~u~. .\f. nhbofti and possibly in 111. ~pretus. The presence of the common variant N chromosome in the house micc of thr various subsprcies in the fauna of the former U.S.S.R.. hlongolia ( m d d r i ) and .Japan (molossinus) provides the hasis Tor the integration of' Asian house mice into the one species, .if. musritlu~ S P~S U sfrido. l ' h c problems of morphology. ecology and systematics of the niousr fauna of thr former U.S.S.R. arc also discussrd with special attention being paid to the studies of the so callrd 'wng~mi' form. ADDI'ITONAL KEY \\'ORDS:-.Uus niitscirluJ ~ karyotype -X chromosome -Y chromosome svstematics.