freemartin
Sign in to savethumb|A plate showing a "Free Martin" from the collected works of John Hunter. A freemartin or free-martin (sometimes martin heifer) is an infertile cow with masculinized behavior and non-functioning ovaries. Such a cow is born as one of a pair of twins, with a male calf as the other twin. Phenotypically, the animal appears female, but various aspects of her female reproductive development were altered due to acquisition of anti-Müllerian hormone from the male twin. Genetically, the animal is chimeric: karyotypy as a sample of cells shows XX/XY chromosomes. The animal originates as a female (X
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9 sectionsContents
- History
- Etymology
- Mechanism
- Diagnosis
- Other animals
- Uses
- Fictional use
- References
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thumb|A plate showing a "Free Martin" from the collected works of John Hunter. A freemartin or free-martin (sometimes martin heifer) is an infertile cow with masculinized behavior and non-functioning ovaries. Such a cow is born as one of a pair of twins, with a male calf as the other twin. Phenotypically, the animal appears female, but various aspects of her female reproductive development were altered due to acquisition of anti-Müllerian hormone from the male twin. Genetically, the animal is chimeric: karyotypy as a sample of cells shows XX/XY chromosomes. The animal originates as a female (XX), but acquires the male (XY) component in utero by exchange of some cellular material from a male twin, via vascular connections between placentas. Such cows provide an example of microchimerism. The chimerism is mainly present in the hematopoietic stem cells.
== History == thumb|The Free-Martin (Sawrey Gilpin) Freemartins are known to have been described by the Roman writer Varro, who called them .