[Genetic and molecular analysis of new recombinant t-haplotypes t(M8) and t(M9)]

The results of genetic and molecular analysis of new recombinant mouse haplotypes tM8 and tM9, derived from tw12 and t12, are described. Data on viability and fertility of tM/tM homozygotes are presented, as well as that on t-chromosome transmission ratio distortion (TRD) in the progeny of heterozygous males. Blot-hybridization analysis was performed using four t-specific probes: Tu48, Tu66, Tu119, and Tu122. Comparison of data obtained in the study with that on the structure of the initial haplotypes suggests that both recombinant haplotypes resulted from unequal crossing-over. In the case of tM9 haplotype, the crossing-over site was probably located in the region of distal t complex inversion, and tM8 haplotype resulted from two crossing-over events in the medial part of t complex.