Chromosome number polymorphism in a litter of European wild boar (Sus scrofa scrofa L.)

Populations of wild boar (Sus scrofa scrofa L.) of Central Europe frequently demonstrate polymorphism in chromosome number. This phenomenon is caused by chromosome rearrangements of the centric fusion type. The presence of Robertsonian translocations in the wild boar population may lead to one of three different karyotypes: 2n=36, 2n=37 and 2n=38. The aim of the study was to analyse the karyotype of five wild boar piglets (two gilts and three boars) originating from one litter, by unknown parents. The GTG-banding technique demonstrated that one boar was characterized by karyotype 38,XY, two gilts (37,XXt.rob15;17) and one boar (37,XYt.rob15;17) were heterozygotic translocation carriers while one boar (36,XYt.rob15;17) was a homozygotic carrier for a Robertsonian translocation including chromosomes 15 and 17. Thus, in this particular litter the chromosome number polymorphism was shown. A Mendelian segregation was found of the 15;17 translocation in the piglets (1:2:1 ratio) whose parents were possibly heterozygotic carriers of 15;17 centric fusion.