title: Preimplantation embryo development (Ped) gene copy number varies from 0 to 85 in a population of wild mice identified as Mus musculus domesticus.
abstract: 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.
authors.affiliation: Department of Biology, Northeastern University, 134 Mugar Hall, Boston, Massachusetts 02115, USA. byrne.mic@neu.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Byrne
authors.forename: Gwilym S
authors.initials: GS
authors.lastname: Jones
authors.forename: Carol M
authors.initials: CM
authors.lastname: Warner
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D018628:Gene Dosage; D005805:Genes, MHC Class I; D005838:Genotype; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D051379:Mice / Q000235:genetics* / Q000276:immunology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D015395:Histocompatibility Antigens Class I; C032907:Q surface antigens; D004247:DNA