Genetic Variation and Systematics of Four Species of Mice of the Peromyscus Boylii Species Group

Genetic variation and systematics of four species of mice of the Peromyscus boylii species group. Syst. Zool. 24:143–162.—The genetic structure of 52 natural populations of four species (P. attwateri, P. boylii, P. pectoralis, and P. polius) of the Peromyscus boylii species group was analyzed through application of chromosomal and electrophoretic techniques. Only slight or no chromosomal variation was observed in three species (attwateri, pectoralis, and polius), but considerable chromosomal variation occurred among populations of P. boylii. Chromosomal evidence indicated that gene flow occurred between two of the chromosomal forms of P. boylii (spicilegus and rowleyi). Analysis of electrophoretic variation in proteins encoded by 17 structural loci of populations of P. boylii, consisting of eight chromosomal forms, indicated that these forms of P. boylii form a conspecific unit. Populations of P. attwateri were genetically distinct from other members of this group, thus supporting the specific status of this form. Examination of specific loci for allelic homology indicated that P. attwateri probably arose from P. boylii. A sample of P. polius suggested that the affinities of this species are with the boylii group. Populations of P. pectoralis demonstrated very low levels of genetic similarity with other members of this species group suggesting that the affinities of P. pectoralis may lie with other forms of Peromyscus.