Chromosomal alterations in the Spanish Breed horses

MIGUEL MORENO MILLÁN; MARIA JOSE MORENO; SEBASTIÁN DEMYDA PEYRÁS

Bucarest

Congreso; 9th Scientific Symposium Prospects in Agriculture and Rural Area Development Bucharest; 2009

University of Veterinary Sciences of Bucharest

In the Cytogenetic laboratory we have studied during the last 10 years a total of 10 mares with reproductive alterations. All of them were carrier of chromosomal alterations. One animal showed a typical gonadal disgenesia. In the cytogenetic analysis the presence of chromosome Y in all examined cells was found. This chromosome constitution is denominated sex-reversal syndrome, alteration quite frequently in the horse. In this case the syndrome is recognized as an animal with mare phenotype and male chromosome constitution (XY). This is the first time in which a case of this syndrome is observed in Spanish breed horse. Other alterations detected were two cases of trisomy in chromosome number 26 in two heterosexual brothers; several cases of XX/XY chimerism and a case, for the first time, of an aneuploidy of sexual chromosomes, having the animal four different cellular types. This animal had a chromosome complement of 63,X0/64,XX/64,XY/65,XXX. In this case we can observe that the animal presented a cellular chimerism XX/XY with a mosacism XX/X0/XXX.