Common vole

microtus_arvalis

microtus_arvalis

Interspecific F1 crosses between different species of the common vole demonstrate  primary non-random X inactivation.  Crosses between  M.arvalis and anothe species of «arvalis» group has active X-cromosome from M.arvalis (Zakian et al 1987).

The common vole is hardly restricted in means of distribution and habitat and inhabits large areas of Eurasia. As Microtus arvalis followed human civilisation, primary and secondary habitats can be distinguished. The primary habitats are everything but dense forests, such as meadows, heath lands, and fallow land. The secondary habitats are mainly agricultural fields whereby shallow sloped areas are preferred. The natural food of the common vole is grass, but it also feeds on many agricultural crops (within secondary habitats) and here its reproduction is faster than in primary habitats.
(From Wikipedia)

systematics of the common voles

Systematics of the common voles

Evolution tree of the voles

Evolution tree of the voles (Mazurok et al 2001)