Polymorphism of t-complex genes in European wild mice

Thirty-two t haplotypes were extracted from wild mice captured in Central Europe, Spain, the Soviet Union, Israel, Egypt, the Orkneys and South and North America, and tested for lethality in the homozygous state. Twenty-two proved to be homozygous lethals, 8 semilethals and 2 viables. The lethal t haplotypes were then tested by the genetic complementation test for identity with representatives of known complementation groups and with each other. Five of the 22 haplotypes proved to carry previously identified lethality factors (t^w5, t^w73, and t^Lub-1), while the rest carried new factors. The 17 haplotypes fell into 8 new complementation groups. Two of the new groups are partially overlapping in that they seem to share some lethality factors and differ in others. These tests raise the total number of known complementation groups to 16. The distribution of the individual t haplotypes among wild mice populations seems to reflect their differentiation from a common ancestor haplotype.