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Summary. Mating tests of males bearing different combinations of alleles near locus T show fertility differences from near sterile to near normal fertility depending on the specific alleles combined. Viable t-alleles with no marked effects on fertility when homozygous, fall into different fertility categories when each is combined with the same lethal allele. The differences are attributed to effects on sperm function exerted by the properties of an important controlling centre in the ninth linkage group.
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L. C. Dunn (1969) studied this question.
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