H-Y antigen
| anti-Müllerian hormone | |
|---|---|
| Identifiers | |
| Symbol | AMH |
| Entrez | 268 |
| HUGO | 464 |
| OMIM | 600957 |
| RefSeq | NM_000479 |
| UniProt | P03971 |
| Other data | |
| Locus | Chr. 19 p13.3 |
| Lysine-Specific Demethylase 5D protein | |
|---|---|
| Identifiers | |
| Symbol | KDM5D |
| Alt. symbols | HYA, SMCY |
| HUGO | 11115 |
| OMIM | 426000 |
| RefSeq | NM_004653 |
| UniProt | Q9BY66 |
| Other data | |
| Locus | Chr. Y q11.223 |
| Male Enhanced Antigen 1 | |
|---|---|
| Identifiers | |
| Symbol | MEA1 |
| Alt. symbols | HYS |
| HUGO | 6986 |
| OMIM | 143170 |
| RefSeq | NM_001318942 |
| UniProt | Q16626 |
| Other data | |
| Locus | Chr. 6 p21.1 |
H-Y antigen is a male tissue specific antigen.[1] Originally thought to trigger the formation of testes (via loci, an autosomal gene that generates the antigen and one that generates the receptor,[2]) it is now known that it does not trigger the formation of testes but may be activated by the formation of testes.[3]
There are several antigens which qualify as H-Y as defined by rejection of male skin grafts in female hosts or detected by cytotoxic T cells or antibodies. One H-Y, secreted by the testis, defined by antibodies, is identical to müllerian-inhibiting substance (AMH gene).[1] Another H-Y, minor histocompatibility antigen, seemed to be encoded in the SMCY gene (acronym for 'selected mouse cDNA on Y'), later identified as an 11-residue peptide from the Lysine-Specific Demethylase 5D protein (KDM5D gene) presented by HLA-B7. A third example is MEA1.
Association with spermatogenesis
It has been shown that male mice lacking in the H-Y antigen, hence lacking in the gene producing it, have also lost genetic information responsible for spermatogenesis.[4] This result also identified a gene on the mouse Y chromosome, distinct from the testis-determining gene, that was essential for spermatogenesis, thus raising the possibility that the very product of this "spermatogenesis gene" is the H-Y antigen.[4]
Male homosexuality and the birth order effect
Among humans, it has been observed that men with more older brothers tend to have a higher chance of being homosexual. For every additional older brother, a man's chance of being homosexual can rise by up to 33%.[5] One theory to explain this involves H-Y antigens, which suggests that a maternal immune reaction to these antigens has, to an extent, an inhibitory effect on the masculinization of the brain, and therefore, the more male foetuses that the mother of a man has had, the greater the maternal immune response towards him[6] and thus the greater the inhibitory effect on brain masculinization, which is believed to be a factor in sexual orientation.[5]
This hypothesis is supported by evidence that older sisters have no discernible influence on the sexual orientation of later-born males, which would be expected since H-Y antigen is male tissue specific, the 'probable involvement of H-Y antigen in the development of sex-typical traits, and the detrimental effects of immunization of female mice to H-Y antigen on the reproductive performance of subsequent male offspring'.[7]
References
- ↑ 1.0 1.1 Müller U (June 1996). "H-Y antigens". Human Genetics. 97 (6): 701–4. PMID 8641682.
- ↑ "H-Y Antigen". mediLexicon. Wolters Kluwer.
- ↑ Wolf U (1998). "The serologically detected H-Y antigen revisited". Cytogenetics and Cell Genetics. 80 (1–4): 232–5. doi:10.1159/000014986. PMID 9678364.
- ↑ 4.0 4.1 Burgoyne PS, Levy ER, McLaren A (1986). "Spermatogenic failure in male mice lacking H-Y antigen". Nature. 320 (6058): 170–2. doi:10.1038/320170a0. PMID 3951555.
- ↑ 5.0 5.1 Ridley M (2000). Genome: The Autobiography of a Species in 23 Chapters. Harper and Collins. ISBN 978-0-06-089408-5.
- ↑ Dare T (8 October 2013). "Vaccination and immunity for iGCSE Biology". YouTube.
- ↑ Blanchard R, Klassen P (April 1997). "H-Y antigen and homosexuality in men". Journal of Theoretical Biology. 185 (3): 373–8. doi:10.1006/jtbi.1996.0315. PMID 9156085.