title: Presumptive Sry-negative XX sex reversal in a llama with multiple congenital anomalies.
abstract: Multiple congenital abnormalities of the external genitalia consistent with XX sex reversal were detected in a juvenile llama. The llama had a typical female karyotype (74, XX) and did not have a Y chromosome, but a minute chromosome was detected. To determine whether a piece of Y chromosome containing the Sry gene might be located in a small translocation, DNA analysis by polymerase chain reaction was performed; the Sry gene was not detected. Histologic examination revealed ovarian tissue, whereas testicular tissue was not found. External genitalia were partially masculinized, indicating that the urogenital sinus, genital tubercle, and genital swellings had been exposed to androgens during development, although the dam had not received exogenous androgens. Testicular tissue in the ovaries may have been undetected or had regressed prior to birth, as has been reported in sex reversal in mice.
authors.affiliation: Department of Large Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Drew
authors.forename: V N
authors.initials: VN
authors.lastname: Meyers-Wallen
authors.forename: G M
authors.initials: GM
authors.lastname: Acland
authors.forename: C L
authors.initials: CL
authors.lastname: Guyer
authors.forename: D N
authors.initials: DN
authors.lastname: Steinheimer
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D001483:Base Sequence; D002161:Camelids, New World / Q000002:abnormalities*; D004247:DNA / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics*; D012734:Disorders of Sex Development; D005260:Female; D005836:Genitalia, Female / Q000002:abnormalities / Q000473:pathology; D007621:Karyotyping / Q000662:veterinary; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012689:Sequence Homology, Nucleic Acid; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors; D014960:X Chromosome
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors; D004247:DNA