Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Poster: Equine
            

PLASTICITY OF TWO SATELLITE DNA SEQUENCES IN EQUIDAE

Dipartimento di Genetica e Microbiologia, Universitą di Pavia, Via Ferrata 1, 27100 Pavia, Italy

Two horse genomic fragments containing pericentromeric satellites were isolated and sequenced: 37cen is composed of tandemly repeated arrays of a 221 bp consensus belonging to the horse major satellite family and 2P1 contains 22-23 bp monomers from the e4/1 family. 37cen and 2P1 were localized on the chromosomes of Equus caballus (ECA), Equus asinus (EAS), and Equus grevyi (EGR) by fluorescence in situ hybridization and the labelled chromosomes were identified by G and R-banding. The pericentromeric location of the two ECA satellites was conserved only in a few EAS and EGR chromosomes. On the contrary, the two horse satellites were preferentially located at terminal positions in the other Equidae. A comparison of the hybridization patterns in the three species was performed using the available data from the literature to identify the orthologous chromosomes. The results suggest that, during the evolution of Equidae, repositioning of several centromeres occurred without movement of satellite DNA and that, in EAS and EGR, the two satellites are not involved in the centromeric function. In addition, the hybridization of 37cen with the EAS chromosomes allowed to describe a frequent polymorphism due to extended deletions of the 1pter region.