Genetical Research

Research Article

Fertility of sperm from t/ + mice: evidence that + − bearing sperm are dysfunctional

Patricia Olds-Clarkea1 and Betsy Peitza2

a1 Department of Anatomy, Temple University School of Medicine, Philadelphia, PA 19140

a2 Department of Biology, California State University at Los Angeles, Los Angeles, CA 90032

Summary

Male mice carrying one complete t haplotype transmit it to virtually all offspring. This implies that either the sperm carrying the t haplotype have an advantage in fertilization, or that the sperm not carrying a t haplotype are dysfunctional. To distinguish between these possibilities, epididymal sperm from tw32/ + and congenic + / + males were artificially inseminated into the uterus of T / + females, and the transmission ratio determined from the phenotype of the offspring. After artificial insemination (AI) of sperm from tw32/ + males, the mean ratio was 0·95 (3 experiments, 5 litters), demonstrating that the transmission ratio remains high after AI into the uterus. After AI of a mixture of equal numbers of motile sperm from tw32/ + and congenic + / + males, the mean ratio was 0·22 (6 experiments, 8 litters). These results suggest that sperm carrying a t haplotype from t/ + males are not superior to sperm from + / + males, and therefore imply that sperm not carrying a t haplotype from t/ + males are dysfunctional.

(Received August 22 1985)

Metrics