Two cases of reciprocal translocations in domestic pigs producing small litters

Two cases of reciprocal translocations in domestic pigs producing small litters

1997

SUMMARY: Two boars of Finnish Yorkshire breed were selected for chromosomal analysis because of their small litters. One had a complex three breakpoint reciprocal translocation where the small distal chromosome segments were fused in new combinations between autosomes 2,9 and 14. This boar with a 2n = 38,XY,t(2;9;14)(q23;q22;q25) karyotype had produced approximately 3.3 piglets per litter and its fertility was reduced by 70% compared to average of litter size in Finnish Yorkshire breed pigs. In another Finnish Yorkshire breed boar, the long arm of autosome 7 had broken and attached to the terminal end of autosome 15. The boar had a 2n = 38,XY, rcp(7q-;15q+)(q24;q26) karyotype. The average of piglets per litter sired by this boar was 5.2 and the litter size was reduced by approximately 50%. The chromosomal rearrangements t(2;9;14) was inherited by four of the boar's offspring studied from two whole litters having seven piglets altogether. Meiotic chromosomes were analysed conventionally from one male translocation carrier offspring of the t(2;9;14) boar. Total sperm count and progressive motility of spermatozoa were within normal limits in one male translocation carrier offspring of the t(2;9;14) boar and in the rcp(7q-;15q+) boar. The two reciprocal translocations seem to have arisen spontaneously in these two boars.

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