Free Access
Genet. Sel. Evol.
Volume 36, Number 6, November-December 2004
Page(s) 663 - 672
Genet. Sel. Evol. 36 (2004) 663-672
DOI: 10.1051/gse:2004023

Mitochondrial D-loop sequence variation among Italian horse breeds

Maria Cristina Cozzia, Maria Giuseppina Strillaccia, Paolo Valiatia, Barbara Bighignolia, Mario Canceddab and Marta Zanottia

a  Istituto di Zootecnica, Facoltà di Medicina Veterinaria, Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy
b  Dipartimento di Biologia Animale, Facoltà di Medicina Veterinaria, Università degli Studi di Sassari, Via Vienna 2, 07100 Sassari, Italy

(Received 3 December 2003; accepted 17 June 2004)

Abstract - The genetic variability of the mitochondrial D-loop DNA sequence in seven horse breeds bred in Italy (Giara, Haflinger, Italian trotter, Lipizzan, Maremmano, Thoroughbred and Sarcidano) was analysed. Five unrelated horses were chosen in each breed and twenty-two haplotypes were identified. The sequences obtained were aligned and compared with a reference sequence and with 27 mtDNA D-loop sequences selected in the GenBank database, representing Spanish, Portuguese, North African, wild horses and an Equus asinus sequence as the outgroup. Kimura two-parameter distances were calculated and a cluster analysis using the Neighbour-joining method was performed to obtain phylogenetic trees among breeds bred in Italy and among Italian and foreign breeds. The cluster analysis indicates that all the breeds but Giara are divided in the two trees, and no clear relationships were revealed between Italian populations and the other breeds. These results could be interpreted as showing the mixed origin of breeds bred in Italy and probably indicate the presence of many ancient maternal lineages with high diversity in mtDNA sequences.

Key words: mitochondrial DNA / D-loop / biodiversity / phylogeny / Italian horse

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© INRA, EDP Sciences 2004