Intra individual variation in the number of B chromosomes in the yellow-necked mouse, Apodemus flavicollis (Mammalia, Rodentia).

The yellow-necked mouse, Apodemus flavicollis, is characterized by a frequent occurrence of B chromosomes. The frequency of intra individual mosaicism of Bs was studied in 995 animals collected at six localities in Serbia. It was found that 329 (33.