title: Reduced meiotic fitness in hybrids with heterozygosity for heterochromatin in the speciating Mus terricolor complex.
abstract: Mus terricolor I, II and III are the three chromosomal species which differ in stable autosomal short-arm heterochromatin variations established in homozygous condition. Analysis of meiosis in the laboratory-generated F1 male hybrids from crosses (both ways) between M. terricolor I and II and between M. terricolor I and III shows high frequencies of pairing abnormalities at pachytene. The backcross (N3 generation) male hybrids between M. terricolor I and II have meiotic abnormalities as in the F1 male hybrids, though to a lesser extent. They show difference in pairing abnormalities in the different karyotypic forms; the backcross hybrids heterozygous for the heterochromatic short arms have more anomalies compared to the homokaryotypic hybrids. This suggests a negative influence of the heterochromatin heterozygosity in meiotic pairing. The results indicate a role for heterochromatin variations in the development of a reproductive barrier in the speciating M. terricolor complex.
authors.affiliation: Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India. tsharma123@yahoo.co.in
authors.forename: Tikaram
authors.initials: T
authors.lastname: Sharma
authors.forename: Amit
authors.initials: A
authors.lastname: Bardhan
authors.forename: Min
authors.initials: M
authors.lastname: Bahadur
mesh_terms: D000818:Animals; D005260:Female; D006570:Heterochromatin / Q000235:genetics*; D006579:Heterozygote; D007621:Karyotyping; D008297:Male; D008540:Meiosis / Q000235:genetics*; D051379:Mice / Q000235:genetics*
chemical_list: D006570:Heterochromatin