DNA profiling reveals remarkably low genetic variability in a herd of SLA homozygous pigs.

Inbred strains of rodents have become indispensable for a wide range of biological studies. It has generally been accepted that genetic uniformity is unlikely to be achieved before 20 generations of brother x sister matings discouraging attempts to inbreed larger mammals. Nevertheless, pigs, homozygous for the swine MHC haplotype SLA b/b, have been inbred at the Babraham Institute for almost thirty years and used for immunological studies. Since the herd had not been studied at the DNA level, DNA profiling at multiple hypervariable loci was performed and surprisingly little genetic polymorphism and extremely high inter-individual resemblance were observed reminiscent of that observed in inbred strains of mice.