Phylogenetic relationships of Argentinean Creole horses and other South American and Spanish breeds inferred from mitochondrial DNA sequences.

P. MIROL; P. PERAL GARCIA; J. VEGA PLA; F. DULOUT

ANIMAL GENETICS

Año: 2002 vol. 33 p. 356 - 363

0268-9146

South American horses constitute a direct remnant of the Iberian horses brought to theNew World by the Spanish conquerors. The source of the original horses was Spain,and it is generally assumed that the animals belonged to the Andalusian, SpanishCeltic, Barb or Arabian breeds. In order to establish the relationship between Argentineanand Spanish horses, a portion of the mitochondrial D-loop of 104 animalsbelonging to nine South American and Spanish breeds was analysed using SSCP andDNA sequencing. The variability found both within and between breeds was very high.There were 61 polymorphic positions, representing 16% of the total sequence obtained.The mean divergence between a pair of sequences was 2.8%. Argentinean Creolehorses shared two haplotypes with the Peruvian Paso from Argentina, and the commonesthaplotype of the Creole horses is identical to one of the Andalusian horses. Evenwhen there was substantial subdivision between breeds with highly significantWright’s Fixation Index (FST), the parsimony and distance-based phylogenetic analysesfailed to show monophyletic groups and there was no clear relationship in thetrees between the South American and any of the other horses analysed. Although thisresult could be interpreted as mixed ancestry of the South American breeds withrespect to the Spanish breeds, it is probably indicating the retention of very ancientmaternal lineages in the breeds analysed.