International Mammalian Genome Society

17th International Mouse Genome Conference

9-12 November 2003, Braunschweig, Germany

Plenary Presentations * Oral Presentations *
Poster Presentations: Behavioural Genetics and Genomics * Development and Stem Cells * Functional Genome Analysis * Mouse Models of Human Disease * Mouse System Biology Bioinformatics * Multigenic and Multifactorial Trait Analysis * Nutrition and Metabolic Disease * Phenotyping Methods Imaging * The Genetics and Genomics of Infectious Disease *
Verne Chapman Memorial Lecture * Table of Contents * Sponsor/Exhibitor List * Awards * Photographs

---

POSTER 156 - GENETIC STUDY ON X-LINKED HYBRID STERILITY IN THE B6-X^PWD INTERSUBSPECIES CHROMOSOME SUBSTITUTION STRAIN

Aixnerová R
Institute of Molecular Genetics AS CR and Centre of Integrated Genomics

Co-Authors: 1) Gregorova S, 1) Divina P, 2) Buckiová D, 1) Landíková M, 1) Forejt J
Institutions: 1) Institute of Molecular Genetics AS CR and Centre of Integrated Genomics, 2) Institute of Experimental Medicine AS CR

Hybrid sterility is a postzygotic reproductive isolation mechanism, which appears in the early stages of speciation of various species. In the house mouse, Mus musculus musculus and Mus musculus domesticus represent recently separated mouse subspecies, particularly suitable for genetic studies of hybrid sterility since the reproductive barrier between them is still incomplete. Here we introgressed the X chromosome of the PWD/Ph inbred strain, derived from M. m. musculus wild mice, into the genetic background of C57BL/6J inbred strain, predominantly of M. m. domesticus origin. The resulting B6-X^PWD/X^B6 females were viable and fertile but B6-X^PWD/Y^B6 males were completely sterile. The hybrid sterility is associated with reduced testes weight, a limited apoptosis of spermatocytes, lower sperm count and spermatozoa with abnormal heads. The QTL analysis revealed the oligogenic nature of sterility: the central and distal parts of the X chromosome were associated with reduced testes weight and the lower sperm count while the central part of the X chromosome was most responsible for the abnormal sperm head morphology and for the fertility impairment measured by the number of offspring. It is well established that hybrid sterility affects preferentially the heterogametic sex (Haldane's rule) and that the X chromosome has enhanced effect on sterility in heterogametic males. These characteristics suggest that the hybrid sterility could arise by a similar mechanism among very different kinds of animals. Mapping and cloning of genes responsible for hybrid sterility in B6-X^PWD/Y^B6 males could help to answer these old questions.