Chromosomal polymorphism in Peromyscus polionotus.

Abstract

Twenty-three oldfield mice, Peromyscus polionotus, representing six sources, were karyotyped. A structural polymorphism involving a moderately small pair of auto-somes was detected. This pair may be either acrocentric or bi-armed, resulting in karyograms showing 12, 12½, and 13 acrocentric pairs. The variation could be attributed to a single inversion widely distributed in the species. Minor structural variations in other autosomes also occurred. The karyotype of the F1 interspecific hybrid of P. maniculatus x P. polionotus was examined. The hybrid had an acro-centric:bi-armed chromosome ratio intermediate to the parent species.