The production, morphology, karyotypes and transport of spermatozoa from tertiary trisomic mice and the consequences for egg fertilization.

Tertiary trisomic males, carrying the small translocation chromosome from the T(1;13)7OH reciprocal mouse translocation as the extra chromosome, are oligospermic. Uterine and oviductal sperm counts were congruent to 10% of normal. Of the uterine spermatozoa, 77-2% were morphologically abnormal compared with 24-6% in the oviduct. Oligospermy in the tertiary trisomic males leads to delayed fertilization; 34-8% of the 109 eggs scored between 5-5--9-5 hr after mating were fertilized compared with 52-1% (n=343) at Day 2. Of the 179 morulae/blastocysts recovered at Day 4, 46-9% contained the small marker chromosome, which agrees with earlier cytological studies on secondary spermatocytes. These results indicate that euploid and aneuploid spermatozoa are formed in about equal numbers and there is no relationship between sperm morphology and karyotype.