ANALYSIS OF CHROMOSOME CONSTITUTION OF HUMAN SPERMATOZOA WITH NORMAL AND ABERRANT HEAD MORPHOLOGIES AFTER INJECTION INTO MOUSE OOCYTES

The chromosome constitution of human spermatozoa was determined after injecting individual spermatozoa into mouse oocytes. Of a total 279 eg gs arrested at first cleavage metaphase, 200 (71.7%) were suitable for the analysis of sperm chromosomes. Incidences of spermatozoa with num erical and structural chromosome aberrations were 1.3 and 6.9% respect ively in spermatozoa with normal head morphology, showing values compa rable with those found in previous studies using the hamster oocyte-hu man sperm fusion system. The ratio of X- to Y-bearing spermatozoa did not differ significantly from the expected 1:1 ratio, The incidence of structural chromosome aberrations was about four times higher in sper matozoa with amorphous, round and elongated heads (26.1%) than in thos e with morphologically normal heads, whereas the incidence of aneuploi dy was not significantly different between the two groups. No increase in chromosome aberrations was found in spermatozoa with large heads, The same was true for spermatozoa with small heads, Although the sampl e size used in this study is rather small, the results nevertheless in dicate that some morphological abnormalities in the sperm heads are as sociated with their chromosome defects.