OMIA:000393-9823 : Tetragametic chimerism (including Freemartin) in Sus scrofa (pig)

In other species: dog , horse , red deer , taurine cattle , sheep , bighorn sheep , water buffalo

Categories: Reproductive system phene

Links to MONDO diseases: No links.

Mendelian trait/disorder: unknown

Considered a defect: yes

Cross-species summary: This is a type of sex chromosome difference of sexual development (DSD). Tetragametic chimerism is a rare, sex chromosome difference of sex development characterized by the two different haploid sets of maternal and paternal chromosomes and variable phenotype - from normal male or female genitalia, to different degrees of ambiguous genitalia, and often infertility. Also, in the cases of monochorionic dizygotic twins, it can be confined to blood of both twins. [updated from Orphanet : 199310 ] Freemartin or free-martin is an infertile female animal which is the twin of a male animal whose anti-Müllerian hormones affected its development in utero. Genetically the animals are chimeric (microchimerism, XX/XY leukocyte chimerism) - some stem cells from the male twin are received during in utero development via vascular connections between placentas. The condition is mostly reported in ruminants due to their multicotyledonary placenta type. Phene was renamed to 'Tetragametic chimerism' [16/11/2022]

Genetic engineering: Unknown
Have human generated variants been created, e.g. through genetic engineering and gene editing

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2005). OMIA:000393-9823: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

1988 Romagnano, A., Tiemann, M., Niar, A., Helie, O., King, W.A. :
[Freemartinism in domestic animals] Medicin veterinaire du Quebec 18:79-84, 1988.
1987 Syed, M., Nes, N., Ronningen, K. :
The significance of chromosome studies in animal breeding in Norway Journal of Animal Breeding and Genetics 104:113-120, 1987.
1982 Ollivier, L., Sellier, P. :
Pig genetics: a review Annales de Genetique et de Selection Animale 14:481-544, 1982.
1970 Somlev, B., Hansen-Melander, E., Melander, Y., Holm, L. :
XX/XY chimerism in leucocytes of two intersexual pigs Hereditas 64:203-210, 1970. Pubmed reference: 5535788.
1968 Bruere, A.N., Fielden, E.D., Hutchings, H. :
XX/XY mosaicism in lymphocyte cultures from a pig with freemartin characteristics New Zealand Veterinary Journal 16:31-38, 1968. Pubmed reference: 5241942. DOI: 10.1080/00480169.1968.33743.
1966 McFee, A.F., Knight, M., Banner, M.W. :
An intersex pig with XX/XY leucocyte mosaicism Canadian Journal of Genetics and Cytology 8:502-505, 1966.
1965 Bertrand, M. :
[Freemartinism] Revue de Medecine Veterinaire 116:575-596, 1965.

Edit History

  • Created by Frank Nicholas on 06 Sep 2005