Polygenic influences on the length of oestrous cycles in inbred mice involve MHC alleles.
Genetic influences on female reproductive cycles were analysed in histocompatibility-congenic strains of mice. Oestrous cycles of young, virgin mice of inbred-congenic strains, hybrid crosses (F1), and parental-hybrid backcrosses (F2) were monitored for 3 months. Oestrous cycles were categorized by length (inter-oestrous interval): 4, 5, 6, or 7-14 days. Mice with the following H-2 haplotypes had a greater proportion of 5-day oestrous cycles: H-2b, H-2r, H-2h2, H-2h4, and H-2i5. In contrast, the H-2k and H-2d haplotypes had mostly 4-day oestrous cycles. Influences of H-2 haplotype were seen on two genetic backgrounds, C57BL/10Sn and C3H. Non-H-2 alleles were also implied by different patterns of cycles between strains with the same H-2b haplotype: C57BL/10Sn with predominantly 5-day cycles vs. C57BL/6J with a mix of 4- and 5-day cycles. The genetic basis for strain differences was investigation in F1 hybrids and their backcrosses. F1 hybrids of an H-2b (C57BL/10Sn; 5-day cycles) and an H-2k (B10.BR; 4-day cycles) strain had mostly 5-day cycles, indicating dominance of an H-2b allele(s). However, F1 hybrids from the reciprocal B6 x B10 cross (both H-2b) also display a preponderance of 5-day cycles, indicating dominance of a non-H-2 autosomal allele from the C57BL/10Sn strain. Among F2 mice, a '4-day' phenotype segregated with homozygosity for the k haplotype (P < 0.05, chi 2). These findings demonstrate the influence of genetic differences at the major histocompatibility complex on oestrous cycles.
Lerner
S P
SP
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown 26506-6108.
Anderson
C P
CP
Harrison
D E
DE
Walford
R L
RL
Finch
C E
CE
D000483:Alleles; D000818:Animals; D003433:Crosses, Genetic; D004971:Estrus / Q000235:genetics*; D005260:Female; D006183:H-2 Antigens / Q000235:genetics; D006239:Haplotypes; D006824:Hybridization, Genetic; D008285:Major Histocompatibility Complex; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D013045:Species Specificity; D013997:Time Factors
D006183:H-2 Antigens