title: A search for a genetic basis for gonosomal univalency in mice.
abstract: The frequencies of cells with XY nonpairing at diakinesis/metaphase I were examined in random-bred ICR-Swiss, partly inbred DCH, and highly inbred DBA/2J and C57BL/6-bgJ mice. The animals in given inbred line displayed homogeneity in the proportion of cells with gonosomal univalents. In DBA/2J, the X and Y remained unpaired in 33.2% of the cells examined, whereas the corresponding frequency in C57BL/6-bgJ was only 7.0%. Previous data of RAPP et al. (1977) showed a low incidence of XY nonassociation in C57BL/6 and high frequencies in the BDF1 hybrid (C57BL6 female X DBA/2 male). We interpret our results, and the previous data of RAPP et al. (1977), to indicate the existence in mice of a genetic polymorphism for XY nonassociation. The DBA/2J strain appears to have factors that predispose to a high frequency of gonosomal univalency.
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D008540:Meiosis; D008677:Metaphase; D051379:Mice / Q000235:genetics*; D008810:Mice, Inbred C57BL / Q000235:genetics; D008811:Mice, Inbred DBA / Q000235:genetics; D012730:Sex Chromosomes / Q000502:physiology*; D014960:X Chromosome / Q000502:physiology*; D014998:Y Chromosome / Q000502:physiology*