Genet. Sel. Evol. 36 (2004) 243-257
DOI: 10.1051/gse:2003061

Geographic distribution of haplotype diversity at the bovine casein locus

Oliver C. Jann^a, Eveline M. Ibeagha-Awemu^a, Ceyhan Özbeyaz^b, Pilar Zaragoza^c, John L. Williams^d, Paolo Ajmone-Marsan^e, Johannes A. Lenstra^f, Katy Moazami-Goudarzi^g and Georg Erhardt<sup>a

a</sup>  Department for Animal Breeding and Genetics, Justus-Liebig University of Giessen, Germany
^b  Department of Zootechnics, Faculty of Veterinary Medicine, University of Ankara, Turkey
^c  Laboratorio de Genetica Bioquimica y Grupos Sanguineos, Facultad Veterinaria, Zaragoza, Spain
^d  Roslin Institute (Edinburgh), Midlothian, Scotland, EH25 9PS, UK
^e  Institute of Zootechnics, Catholic University of Sacred Heart, Piacenza, Italy
^f  Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
^g  INRA-LGBC, Domaine de Vilvert, 78352 Jouy-en-Josas, France

(Received 1 October 2002; accepted 10 September 2003)

Abstract
The genetic diversity of the casein locus in cattle was studied on the basis of haplotype analysis. Consideration of recently described genetic variants of the casein genes which to date have not been the subject of diversity studies, allowed the identification of new haplotypes. Genotyping of 30 cattle breeds from four continents revealed a geographically associated distribution of haplotypes, mainly defined by frequencies of alleles at CSN1S1 and CSN3. The genetic diversity within taurine breeds in Europe was found to decrease significantly from the south to the north and from the east to the west. Such geographic patterns of cattle genetic variation at the casein locus may be a result of the domestication process of modern cattle as well as geographically differentiated natural or artificial selection. The comparison of African Bos taurus and Bos indicus breeds allowed the identification of several Bos indicus specific haplotypes (CSN1S1*C-CSN2*A ²-CSN3*A _I / CSN3*H ) that are not found in pure taurine breeds. The occurrence of such haplotypes in southern European breeds also suggests that an introgression of indicine genes into taurine breeds could have contributed to the distribution of the genetic variation observed.

Key words: casein / haplotype / Bos taurus / Bos indicus / phylogeny

Correspondence and reprints: Georg Erhardt Georg.Erhardt@agrar.uni-giessen.de

© INRA, EDP Sciences 2004