The bottom line is, in the racing world, a âniceâ horse is not as important as a âwinningâ horse. Below: Mountain Horses must be certified for both gait and temperment before breeding, to ensure the best traits get passed on to the next generation.
Exceptions to these generalisations happen in the cases of XX males or XY females, or other syndromes. This system is in contrast with the ZW sex-determination system found in birds, some insects, many reptiles, and other animals, in which the heterogametic sex is female.
Overview. 47, XYY syndrome is characterized by an extra copy of the Y chromosome in each of a male's cells. Males with this condition typically do not have unusual physical features and usually have normal sexual development and are able to father children.7, XYY syndrome is characterized by an extra copy of the Y chromosome in each of a male's cells. Males with this condition typically do not have unusual physical features and usually have normal sexual development and are able to father children.