Studies on The Chromosomes of Three Species of Wood Mice

The karyotypes of three species of wood mice have been studied by banding techniques (G-,C- and Ag-staining).Three species have the same diploid number,2n=48.All chromosomes in the complement of A.draco are acrocentrics.The karyotype of A.peninsulae consists of 22 pairs of acrocentrics,1 pair of metacentrics,X and Y are acrocentrics.However,the karyotype of A.latronum consists of 13 pairs of acroentrics,2 pair of subacrocentrics,1 pair of submetacentric,7 pairs of metacentrics,X chromosome is a acrocentric.The G-banded,C-banded and silver-stained karyotypes have been observed.G-banding allows to identify all chromosome pairs in three species.C-banding reveals centromeric heterochromatin in all chromosomes in A.draco.In the C-banded karyotype of A.peninsulae,the centromeric heterochromatin is found in all chromosomes,however,the centromeric C-bands of Nos.7,11,15,21,22 are very fanitly stained even negative,there are also telomeric C-bands in Nos.2,4,7.The Y chromosomes of A.draco and A.peninsulae are whole heterochromatin.The centromeric C-bands of all chromosomes are positive in the C-banded karyotype of A.latronum,but the centromeric C-bands in Nos.3,4,10,12,13 are very fanitly stained.Ag-NORs are predominantly located at Nos.7,8,18,21,22 in A.draco.While Ag-NORs are found in Nos.7,8 in A.peninsulae and A.latronum,respectively.The polymorphism of Ag-NORs of No.22 (in A.draco) and No.7 (in A.peninsulae and A.latronum) is found.Moreover,the classification of three species has also been discussed.