Genetic diagnosis of sex chromosome aberrations in horses based on parentage test by microsatellite DNA and analysis of X- and Y-linked markers.
BACKGROUND
Sex chromosome aberrations are often associated with clinical signs that affect equine health and reproduction. However, abnormal manifestation with sex chromosome aberration usually appears at maturity and potential disorders may be suspected infrequently. A reliable survey at an early stage is therefore required.


OBJECTIVE
To detect and characterise sex chromosome aberrations in newborn foals by the parentage test and analysis using X- and Y-linked markers.


METHODS
We conducted a genetic diagnosis combined with a parentage test by microsatellite DNA and analysis of X- and Y-linked genetic markers in newborn light-breed foals (n = 17, 471). The minimum incidence of sex chromosome aberration in horses was estimated in the context of available population data.


RESULTS
Eighteen cases with aberrations involving 63,XO, 65,XXY and 65,XXX were found. The XO, XXY (pure 65,XXY and/or mosaics/chimaeras) and XXX were found in 0.15, 0.02 and 0.01% of the population, respectively, based solely on detection of abnormal segregation of a single X chromosome marker, LEX003.


CONCLUSIONS
Detection at an early age and understanding of the prevalence of sex chromosome aberrations should assist in the diagnosis and managment of horses kept for breeding. Further, the parental origin of the X chromosome of each disorder could be proved by the results of genetic analysis, thereby contributing to cytogenetic characterisation.
Kakoi
H
H
Laboratory of Racing Chemistry, 1731-2 Tsuruta-cho, Utsunimiya 320-0851, Japan.
Hirota
K
K
Gawahara
H
H
Kurosawa
M
M
Kuwajima
M
M
D000818:Animals; D001483:Base Sequence; D001947:Breeding; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D006734:Horse Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D006736:Horses / Q000235:genetics*; D008297:Male; D008403:Mass Screening / Q000662:veterinary; D018895:Microsatellite Repeats; D010375:Pedigree; D012729:Sex Chromosome Aberrations / Q000662:veterinary*; D014960:X Chromosome; D014998:Y Chromosome
D005819:Genetic Markers