Karyotypic analyses of the genus <i>Neotoma</i> (Cricetidae, Rodentia)

Abstract

Examination of 154 specimens representing nine species of the genus Neotoma revealed diploid numbers of 38, 52, 54 and 56. Six species had the diploid number of 52. Extensive polymorphism was found in two species, N. lepida and N. micropus. Chromosomal variation in the subgenus Neotoma was primarily in Fundamental Number and not in diploid number.

Cladistical analysis of primitive G-band sequences for the karyotype of the ancestor of the Cricetidae complex of rodents

“…In the karyotypes examined, almost all chromosomes were acrocentric. The evidence appears to support the hypothesis that the 14 largest autosomal pairs were acrocentric in the primitive forms, which is compatible with Baker and Mascarello's (1969) proposal that a diploid number between 48 and 52 consisting of mostly acrocentric elements is the most likely primitive karyotypic condition for the cricetids. We suggest that a 2n = 48 54 may well encompass the primitive condition for Cricetidae and Muridae and that this diploid number will likely prove to encompass the primitive condition for most genera in these families.…”

Chromosomal, Electrophoretic, and Breeding Studies of Selected Populations of Deer Mice (Peromyscus maniculatus) and Black-Eared Mice (P. melanotis)

“…The following discussion will serve to show the relationship of our data to Brown's model. 1) Hsu and Arrighi (1968) and Baker and Mascarello (1969) hypothesized that the primitive karyotype for Peromyscus was 48 with a large number of acrocentrics. In the P. maniculatus complex the populations with higher numbers of acrocentrics are found in the peripheral isolates ( Fig.…”

Extensive genome reorganization in the African rodent genus Otomys

“…Evidence suggests that a diploid number of 2n = 48-52, consisting primarily of acrocentric chromosomes, is the most likely primitive karyotype for both the Muridae and Cricetidae (Baker & Mascarello, 1969;Koop et al, 1984). Consequently, although considerable primitive G-band pattern homology was evident from comparisons of several diverse rodent species whose diploid numbers range from 2n = 48-54 (Koop et al, 1984), far less homology is to be expected with the 2n = 28 Otomys karyotypes.…”