Differing mechanisms of meiotic segregation in spermatozoa from three carriers of a pericentric inversion of chromosome 8

Objective To determine the meiotic segregation of a pericentric inversion of chromosome 8 in three carriers. Design Analysis of sperm nuclei by fluorescence in situ hybridization (FISH). Setting University hospital. Patient(s) Three males with an inv(8). Intervention(s) Triple FISH with the 8q and 8p subtelomeres and the specific alphoid of chromosome 9 probes. Main Outcome Measure(s) Meiotic segregation differences between carriers. Result(s) The frequencies of nonrecombinant gametes were 97%, 60.94%, and 61.03%. The frequencies of recombinant sperm were 1.44%, 37.71%, and 37.70%, whereas the size of the inverted segment represented 31%, 61%, and 80% of the size of the whole chromosome 8. Conclusion(s) Many factors seem to influence the production of recombinant chromosomes: the affected chromosome and involved region, location of the breakpoints, or size of the inverted segment. Our results show that the rate of recombination varies principally according to the size of the inverted segment.