Preimplantation embryo development (Ped) gene copy number varies from 0 to 85 in a population of wild mice identified as Mus musculus domesticus

• Published in: Mammalian genome Vol. 18; no. 11; pp. 767 - 778
• Main Authors: Byrne, Michael J, Jones, Gwilym S, Warner, Carol M
• Format: Journal Article
• Language: English
• Published: United States New York : Springer-Verlag 01-11-2007; Springer Nature B.V
• Subjects: Animals; Animals, Wild - genetics; Animals, Wild - immunology; Base Sequence; DNA - genetics; DNA Primers - genetics; Evolution, Molecular; Female; Gene Dosage; Genes, MHC Class I; Genotype; Histocompatibility Antigens Class I - genetics; Humans; Mice - genetics; Mice - immunology; Molecular Sequence Data; Mus musculus domesticus; Polymerase Chain Reaction; Pregnancy; Species Specificity
• ISSN: 0938-8990; 1432-1777
• DOI: 10.1007/s00335-007-9067-8

The preimplantation embryo development (Ped) gene regulates the rate of preimplantation embryonic cleavage division and subsequent embryo survival. In the mouse, the Ped gene product is Qa-2 protein, a nonclassical MHC class I molecule encoded by four tandem genes, Q6/Q7/Q8/Q9. Most inbred strains of mice have all four genes on each allelic chromosome, making a total of eight Qa-2 encoding genes, but there are a few strains that are missing all eight genes, defining a null allele. Mouse strains with the presence of the Qa-2 encoding genes express Qa-2 protein and produce embryos with a faster rate of preimplantation embryonic development and a greater chance of embryo survival compared to mouse strains with the null allele. There is extensive evidence that the human homolog of Qa-2 is HLA-G. HLA-G in humans, like Qa-2 in mice, is associated with enhanced reproductive success. The human population is an outbred population. Therefore, for a better comparison to the human population, we undertook an investigation of the presence of the genes encoding Qa-2 in an outbred population of mice. We used Real-Time Quantitative PCR to quantify the number of Qa-2 encoding genes in a population of 32 wild mice identified as Mus musculus domesticus both by morphologic assessment and by PCR analysis of their DNA. We found great variability in the number of Qa-2 encoding genes in the wild mice tested. The wild mouse with the highest number of Qa-2 encoding genes had 85 such genes, whereas we discovered one wild mouse without any Qa-2 encoding genes. Evolutionary implications of a range of Qa-2 encoding gene numbers in the wild mouse population are discussed, as well as the relevance of our findings to humans.