a1 Institute of Animal Genetics, Edinburgh, 9
Tabby males were irradiated with 500 r and mated to Bn Mobr♀♀. Daughters conceived during the first 3 weeks after irradiation were tested for the presence of sex-linked recessive mutations in their progeny, each daughter representing one irradiated gamete. One visible, but no lethal, was found in the Bn–Mobr segment among 154 tested gametes; one gamete was proved free of lethals or visibles in the Bn–Ta segment, and 21 gametes in the Ta–Mobr segment. Among the whole 176 tested gametes there was no indication of a lethal in the adjoining segments.
(Received April 30 1962)
* Agricultural Research Council Unit of Animal Genetics.