ANALYSIS OF SPERM CHROMOSOME COMPLEMENTS FROM A MAN HETEROZYGOUS FOR A PERICENTRIC-INVERSION OF CHROMOSOME-1

Human sperm chromosomes were studied in a man heterozygous for a peric entric inversion of chromosome (1)(p31q12). Q-banded pronuclear chromo somes were analyzed after in vitro penetration of golden hamster oocyt es. A total of 159 sperm were examined: 54% bearing the inverted chrom osome 1 and 46% the normal chromosome 1. These frequencies are not sig nificantly different from the theoretical 1:1 ratio. There were no rec ombinant sperm with duplications or deficiencies, suggesting that a pa iring loop failed to form or that crossing-over was suppressed. The fr equency of abnormalities unrelated to the inversion was 5% for numeric al, 8.8% for structural, 2.5% for numerical and structural, values not significantly different from control donors studied in our lab. The f requencies of X- and Y-bearing sperm were 46% and 54%, respectively, n ot significantly different from the expected value of 50%. This is the fifth pericentric inversion studied by human sperm chromosome analysi s; recombinant chromosomes have been observed in two of the five cases . Some of the factors associated with an increased risk of recombinant sperm appear to be inversion size greater than 30% of the chromosome and chromosome breakpoints in G-light bands.