Male-mediated introgression of Bos indicus genes into Argentine and Bolivian Creole cattle breeds.

G. GIOVAMBATTISTA; V. RIPOLI; J. DE LUCA,; P. MIROL; J. LIRON; F. DULOUT

ANIMAL GENETICS

Año: 2000 vol. 31 p. 302 - 305

0268-9146

The geographic distribution and frequency ofBos taurus and Bos indicus Y chromosomehaplotypes amongst Argentine and BolivianCreole cattle breeds were studied, using cytogeneticand molecular genetic techniques. A completecorrespondence between Y chromosomemorphology and the haplotype of the Y-linkedmicrosatellite marker INRA 124 was found in allmales examined. The taurine and indicine haplotypeswere detected in 85·7 and 14·3% of themales studied, respectively, although these frequenciesvaried amongst the different breedsexamined. The geographic distribution of thispolymorphism suggests a pattern of zebu introgressionin South America. The highest frequenciesof the Zebu Y-chromosome are found inBrazilian populations (43–90%), in the easternpart of the continent, while it is absent in thesouthermost breeds from Uruguay and Argentina.Bolivan breeds, at the centre of thecontinent, exhibit intermediate values (17–41%). This east:west and north:south gradientof male Zebu introgression could be explainedby historical events and environmental factors.