An assessment of the nature of chromosomal rearrangements in 18 species of <i>Peromyscu</i><i>s</i> (Rodentia: Cricetidae)

Abstract

G- and C-banded karyotypes from 9 previously unstudied species of Peromyscus are described and compared to the 9 species described in the literature. Additional new data are presented for P. eremicus. A hypothetical evolutionary tree for the 18 species was constructed based on the assumption that, where possible, shared chromosomal rearrangements became established in a common ancestor. A minimum of 60 chromosomal rearrangements (34 heterochromatic additions and 26 pericentric inversions) were needed to construct the most parsimonious tree. Seven of the 18 species have heterochromatin in noncentromeric areas. Three times as many inversions have been identified in the 11 largest pairs as have been observed in the 12 smallest pairs. Peromyscine rodents are characterized by a pattern of chromosomal variation quite distinct from that described for other rodent genera, such as Sigmodon and Mus. Karyotypic orthoselection in rodents appears to be relatively common in closely related species.

Resolving Systematic Relationships With G-bands: a Study of Five Genera of South American Cricetine Rodents

“…What is clear is that examination of additional species will not result in many additional chromosomal synapomorphies at the base of the cladogram for the oryzomyine-neotomine-peromyscine rodents. The early stages of evolution for these groups do not appear to have been characterized by extensive chromosomal evolution (Elder, 1980;Robbins and Baker, 1981;Koop et al, 1984a, b). However, within Oryzomys (Fig.…”

Comparative cytogenetics of spiny rats of the genus Proechimys (Rodentia, Echimyidae) from the Amazon region

“…An alteration in the amount and distribution of heterochromatin has been considered one of the most common forms of chromosome evolution in mammals (Baker et al, 1987), as it influences the pairing of the homologues in mutation events and gene recombination events and consequently affects the speciation process (Robbins and Baker, 1981). Specifically for P. gr.…”

Chromosomal evolution in Rodentia

“…Of these, conventional banding analysis showed a high degree of karyotypic conservation within Peromyscus: all species have 2n¼48. The number of chromosomal arms ranges from 52 to 92 because of variation attributable to heterochromatin additions and pericentric inversions (Robbins and Baker, 1981;Rogers et al, 1984). On the basis of the painting data, it seem reasonable to consider the P. eremicus karyotype as being close to the putative ancestral state for Muroidea (Romanenko et al, 2007b).…”