Breakpoint characterization: a new approach for segregation analysis of paracentric inversion in human sperm

Paracentric inversions (PAI) are structural chromosomal rearrangements generally considered to be harmless. Nevertheless, cases of viable recombinants have been reported, indicating the interest of studying the meiotic behaviour of these chromosomal abnormalities. To date, the few studies reported have been performed using either the human-hamster fertilization system or fluorescence in situ hybridization with centromeric or telomeric DNA probes. In order to improve the assessment of meiotic segregation in PAI, we present a new strategy based on the use of bacterial artificial chromosome (BAC) probes which allow a precise localization of chromosome breakpoints and the identification of all meiotic products in human sperm. Sperm samples from carriers of an inv(5) and an inv(14) were used to test this new high-resolution procedure.