Evolutionary conservation of linkage groups: Additional evidence from murid and cricetid rodents

In Mus musculus, family Muridae, the glucosephosphate isomerase (Gpi-1), pink-eyed dilution (p), albinism (c), and -type globin (Hbb) loci are known to be linked in the order Gpi-1-p-c-Hbb. In Rattus norvegicus, another murid rodent, the p, c, and Hbb loci are known to be linked in the same order and with similar recombination frequencies. In Peromyscus maniculatus, family Cricetidae, it was previously known that p and c are linked and by analogy to Mus musculus that linkage group should be bounded by Gpi-1 near p and by a -globin locus near c. Linkage has now been established between Gpi-1 and the Hbe globin locus in Peromyscus. However, the observed recombination frequency in Peromyscus (16.3%) is significantly lower than in Mus, suggesting that perhaps a chromosomal inversion has occurred during the evolutionary divergence of the two rodent families. Linkage relationships were also tested between the Hbc ¹, Hbd ¹, and Hbe ¹ globin variants. Hbc ¹ (presumably an -type globin) segregated independently from Hbd ¹ and Hbe ¹ (presumably -type globins). No recombination was observed between Hbd ¹ and Hbe ¹. Those two globin genes may be alleles at a single locus, although circumstantial evidence suggests that they represent tightly linked duplicate loci.This work was supported by NSF DEB7716104 and by the Committee on Research, UCR.