title: X chromosome control of meiotic chromosome synapsis in mouse inter-subspecific hybrids.
abstract: Hybrid sterility (HS) belongs to reproductive isolation barriers that safeguard the integrity of species in statu nascendi. Although hybrid sterility occurs almost universally among animal and plant species, most of our current knowledge comes from the classical genetic studies on Drosophila interspecific crosses or introgressions. With the house mouse subspecies Mus m. musculus and Mus m. domesticus as a model, new research tools have become available for studies of the molecular mechanisms and genetic networks underlying HS. Here we used QTL analysis and intersubspecific chromosome substitution strains to identify a 4.7 Mb critical region on Chromosome X (Chr X) harboring the Hstx2 HS locus, which causes asymmetrical spermatogenic arrest in reciprocal intersubspecific F1 hybrids. Subsequently, we mapped autosomal loci on Chrs 3, 9 and 13 that can abolish this asymmetry. Combination of immunofluorescent visualization of the proteins of synaptonemal complexes with whole-chromosome DNA FISH on pachytene spreads revealed that heterosubspecific, unlike consubspecific, homologous chromosomes are predisposed to asynapsis in F1 hybrid male and female meiosis. The asynapsis is under the trans- control of Hstx2 and Hst1/Prdm9 hybrid sterility genes in pachynemas of male but not female hybrids. The finding concurred with the fertility of intersubpecific F1 hybrid females homozygous for the Hstx2(Mmm) allele and resolved the apparent conflict with the dominance theory of Haldane's rule. We propose that meiotic asynapsis in intersubspecific hybrids is a consequence of cis-acting mismatch between homologous chromosomes modulated by the trans-acting Hstx2 and Prdm9 hybrid male sterility genes.
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Tanmoy
authors: T
authors: Bhattacharyya
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Radka
authors: R
authors: Reifova
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Sona
authors: S
authors: Gregorova
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Petr
authors: P
authors: Simecek
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Vaclav
authors: V
authors: Gergelits
authors: Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czech Republic.
authors: Martin
authors: M
authors: Mistrik
authors: Research Facility Studenec, Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
authors: Iva
authors: I
authors: Martincova
authors: Research Facility Studenec, Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
authors: Jaroslav
authors: J
authors: Pialek
authors: Mouse Molecular Genetics Group, Division BIOCEV, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors: Jiri
authors: J
authors: Forejt
mesh_terms: D000818:Animals; D023902:Chromosome Pairing / Q000235:genetics*; D005260:Female; D056426:Genetic Loci / Q000235:genetics*; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics*; D006801:Humans; D006824:Hybridization, Genetic; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D008540:Meiosis; D051379:Mice; D040641:Quantitative Trait Loci / Q000235:genetics; D060047:Reproductive Isolation; D013573:Synaptonemal Complex / Q000235:genetics; D014960:X Chromosome / Q000235:genetics*
chemical_list: D011495:Histone-Lysine N-Methyltransferase; C534829:prdm9 protein, mouse