Evolutionary Relationships in Peromyscus: Congruence in Chromosomal, Genic, and Classical Data Sets

Abstract

G- and C-banded karyotypes are presented for Peromyscus pirrensis (subgenus Isthmomys) and P. perfulvus and P. nudipes (subgenus Peromyscus). These data for P. pirrensis are the first reported for the subgenus Isthmomys. The karyotype of this species is unique for the Peromyscus thus far studied in three chromosomal conditions, and these data are interpreted as being compatible with the hypothesis that the subgenus Isthmomys may be the first lineage to diverge from the other Peromyscus (sensu Hooper, 1968). Using data for the 30 species of Peromyscus thus far studied by G- and C-banding, the systematic value of chromosomal banding studies within the genus is assessed by comparing the conclusions from a cladistical analysis of the data with proposed relationships based on morphological and biochemical data. It is shown that a cladogram (generated by the most parsimonious placement of detectable chromosome rearrangements, including reversals and convergences) is largely compatible with the systematic rearrangement proposed by Hooper (1968). In several places where the morphology and genic data are inconclusive, the chromosomal data are also inconclusive.