A Pronounced Sex Difference in Recombination Values in the Sixth Chromosome of the House Mouse

Abstract

THE loci be (belted), Ca (Caracul), and N (naked) constituting the sixth linkage group in Mus musculus are closely linked and in the order be—Ca—N. Linkage of Ca and N was established by Cooper¹. He obtained the recombination values 2.64 per cent in males and 0 per cent in females, the difference not being significant on the total number of mice bred (335). Murray and Snell² discovered the factor be and established the order be—Ca—N. On combining their own data with those of Cooper, they obtained a significant sex difference (probability 0.043) for the segment Ca—N, there being 12 recombinants out of 392 mice bred from backcrossed heterozygous males, while no recombinants were found among 158 mice bred from heterozygous females. For the segment be—Ca they obtained the recombination value 11.49 per cent, with no significant difference between the sexes.