A sporadic case of the sex-reversed mare (64,XY; SRY-negative): molecular and cytogenetic studies of the Y chromosome

The association of abnormal chromosome constitutions and disorders of sex development in domestic animals has been recorded since the beginnings of conventional cytogenetic analysis. Deviated karyotypes consisting of abnormal sex chromosome sets (e.g. aneuploidy) and/or the coexistence of cells with different sex chromosome constitutions (e.g. mosaicism or chimerism) in an individual seem to be the main causes of anomalies of sex determination and sex differentiation. Molecular cytogenetics and genetics have increased our understanding of these pathologies, where human and mouse models have provided a substantial amount of knowledge, leading to the discovery of a number of genes implicated in mammalian sex determination and differentiation. Additionally, other genes, which appeared to be involved in ovary differentiation, have been found by investigations in domestic species such as the goat. In this paper, we present an overview of the biology of mammalian sex development as a scientific background for better understanding the body of knowledge of the clinical cytogenetics of disorders of sex development in domestic animals. An attempt to summarize of what has been described in that particular subject of veterinary medicine for each of the main mammalian domestic species is presented here.

Section: Equine Sex Reversal Syndromementioning

confidence: 99%

Classical and Molecular Cytogenetics of Disorders of Sex Development in Domestic Animals

Villagómez

Parma

Radi

et al. 2009

“…Familial patterns of inheritance have been described, particularly in certain Arabian horse sire lines (Kieffer et al, 1976;Kent et al, 1986;Bowling et al, 1987). Molecular testing of these horses may identify a deletion of or a non-functional SRY gene (Pailhoux et al, 1995;Abe et al, 1999;Mäkinen et al, 1999;Bugno et al, 2003).…”

Section: Sex-reversal Syndromesmentioning

confidence: 99%

Equine clinical cytogenetics: the past and future

Lear

Bailey

2008

Cytogenetic analyses of horses have benefited the horse industry by identifying chromosomal aberrations causing congenital abnormalities, embryonic loss and infertility. Technical advances in cytogenetics enabled the identification of chromosome specific aberrations. More recently, advances in genomic tools have been used to more precisely define chromosome abnormalities. In this report we review the history of equine clinical cytogenetics, identify historical landmarks for equine clinical cytogenetics, discuss how the current use of genomic tools has benefited this area, and how future genomics tools may enhance clinical cytogenetic studies in the horse.

“…The important role of SRY in testis differentiation has been demonstrated in XY sex reversed female horses that lack the SRY factor (Kent et al, 1996;Makinen et al, 2001;Bugno et al, 2003). These horses showed normal external genitalia but had hypoplastic ovaries.…”

Section: Discussionmentioning

confidence: 99%

“…The intersex horse described in this report was characterized by male pseudohermaphroditism, one type in the general syndrome of intersexuality. Male pseudohermaphroditism is the most common type of intersexuality in domestic animals and several cases have been described previously in horses (Meyers-Wallen, 1993;Milliken et al, 1995;MeyersWallen et al, 1997;Buoen et al, 2000;Bugno et al, 2003). The karyotypes of various intersex animals were described as: 64,XX (Meyers-Wallen et al, 1997;Buoen et al, 2000), 65,XXX (Moreno-Millan et al, 1989), 64,XX/64,XY (Basrur, 1970), 63,X/65,XYY (Höhn et al, 1980;Paget et al, 2001), 64,XX/63,X (Kuiper and Distl, 2007).…”

Section: Discussionmentioning

confidence: 99%

A case of an intersex horse with 63,X/64,XX/65,XX,del(Y)(q?) karyotype

Bugno

Ząbek²,

Golonka³

et al. 2008

Cytogenetic and molecular genetic studies of an intersex horse have been carried out. The investigated animal had overall male body conformation; however, its external genitalia consisted of incompletely developed vulva and penis. The X and Y chromosome painting probes detected three cell lines in the examined horse: 63,X, 64,XX and 65,XX with a fragment of a Y chromosome (del Y). The DNA analysis with the PCR and PCR/RFLP methods showed absence of SRY,AMELY and ZFY genes as well as of six Y microsatellite markers (YM2, YP9, YJ10, YE1, YH12, and YA16). These results suggest that the Y chromosome fragment detected in the investigated animal was the result of a deletion of a euchromatic fragment comprising the above-mentioned markers.