Greater genetic variability in Argentine Creole than in Thoroughbred horses based on serum protein polymorphisms.

DIAZ, S.; DULOUT, F.N.; PERAL-GARCIA, P

GENETICS AND MOLECULAR BIOLOGY

Sociedade Brasileira de Genetica

Año: 2002 vol. 1 p. 261 - 265

1415-4757

Genetic polymorphism was analyzed for five blood proteins: albumin - Al, esterase - Es, á1B-glycoprotein - Xk, transferrin - Tf and hemoglobin - Hb in 200 Thoroughbred (TB) and 124 Argentine Creole (AC) horses. Of the five systems examined, Tf and Hb were not in Hardy-Weinberg equilibrium in either breed and Es was not in equilibrium in the Creole breed. Genetic variability, estimated as average heterozygosity, was higher in AC (H = 0.585 ± 0.131) than in TB (H = 0.353 ± 0.065). The genetic differentiation between these two populations (FST) was 0.109. Thus, of the total genetic differences between breeds, the proportion of genetic variation attributable to breed differences was about 10%; the remaining 90% was due to individual variation within breeds. The high degree of genetic variability seen in Argentine Creole horses could be a consequence of natural selection. Selection of TB through the centuries has most likely modified the gene pool of the ancestral population, with a consequent reduction in variability at certain loci. Probably, different mechanisms exist for maintaining polymorphism at these loci in TB and in AC horses. Heterozygosity may have played a fundamental role in adaptation.