A PERICENTRIC-INVERSION OF CHROMOSOME-4 IN PIGS

The main French porcine artificial insemination centre recently decide d to carry out a systematic chromosomal evaluation of the animals used for pure-breeding purposes. This practice has allowed the identificat ion of a new pericentric inversion affecting chromosome 4, in four Lar ge White boars originating from four different herds. The cytogenetic evaluation by means of the GTG-banding technique revealed an inversion of tile pericentric part of the chromosome, after double breaks, the first one in the 4q2.3 pale band of the long arm, and the second one i n the upper border of the 4p1.4 dark band of the short arm. The chromo somal rearrangement could be described, according to the standard nome nclature, as 38,XY,inv(4) (p14q23). This interpretation has been confi rmed by in situ hybridization of the cosmid BHT12 located on the 4p1.5 band. This chromosomal abnormality has no significant effect on produ ction or reproductive performance of carrier animal. A rather old and common origin of the abnormality is hypothesized.