EFFECT OF A HIGH RADIATION BACKGROUND ON MICE CARRYING LETHAL T-HAPLOTYPES

To study the effect of a high radiation background on the structure an d function of the T-complex, we used laboratory mice carrying t-haplot ypes of four complementation groups (t(0), t(12), t(w1), and t(w5)). I n 1987-1989, the animals were kept each year for a month within a 30-k ilometer zone of Chernobyl Nuclear Power Station in regions with diffe rent degrees of pollution. Subsequent genetic analysis revealed a decr ease in fertility, fecundity, and the index of preferable transmission of t-carrying chromosomes in radiated animals and some of their proge ny. The effect of different radiation doses on these parameters was di fferent in animals with various t-haplotypes. A lack of complementatio n or a decrease in the complementation effect was revealed in a number of crosses involving the progeny of irradiated animals; The frequency of complementation distortion was about 8 x 10(-2), which is more tha n an order higher than the usual recombination frequency characteristi c of these t-haplotypes.