Abstract
Genes comprising the major histocompatibility complex (MHC) play a central role in governing the immune response of vertebrates. A great deal of information has been revealed on the molecular biology and physiology of these loci, but three features-the high polymorphism, tight linkage among the loci, and the nonrandom association of alleles-make the system of particular interest from the perspective of population genetics. Information on the dynamic evolutionary forces that have acted on a locus can be inferred from the number and distribution of alleles that it carries. Ten loci from the HLA region of the human MHC, each sampled from several different populations, have been examined for departures from the expected value of homozygosity under the condition of selective neutrality. The homozygosities of five class I and II loci that code for membrane glycoproteins, HLA-A, -B, -C, -DR, and -DQ, and of glyoxylase I (GLO) were significantly less than the neutrality expectations. This suggests the presence of some form of balancing selection. In spite of being closely linked, in fact, located between the class I and class II histocompatibility loci, the homozygosities of the four class III or complement loci C2, Bf, C4A, and C4B, which are detected by electrophoresis, were indistinguishable from, or exceeded, that expected under neutrality. Although this conforms to the suggestion that, in general, electrophoretic variants are neutral, because of the tight linkage to loci demonstrating a history of selection, it is possible that the mechanism for generating variation in the class III loci may be different from that of the class I and class II loci.
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Selected References
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- Bertrams J., Hintzen U., Schlicht V., Schoeps S., Gries F. A., Louton T. K., Baur M. P. Gene and haplotype frequencies of the fourth component of complement (C4) in type 1 diabetics and normal controls. Immunobiology. 1984 May;166(4-5):335–344. doi: 10.1016/S0171-2985(84)80012-1. [DOI] [PubMed] [Google Scholar]
- Busi B. R., Wells L. J., Volkers W. S., Ebeli-Struijk A. C., Meera Khan P. Distribution of glyoxalase I (GLO) variants in Western Europe and the Indian subcontinent. Hum Genet. 1979 May 23;49(1):105–113. doi: 10.1007/BF00277692. [DOI] [PubMed] [Google Scholar]
- Carroll M. C., Campbell R. D., Bentley D. R., Porter R. R. A molecular map of the human major histocompatibility complex class III region linking complement genes C4, C2 and factor B. Nature. 1984 Jan 19;307(5948):237–241. doi: 10.1038/307237a0. [DOI] [PubMed] [Google Scholar]
- Carroll M. C., Palsdottir A., Belt K. T., Porter R. R. Deletion of complement C4 and steroid 21-hydroxylase genes in the HLA class III region. EMBO J. 1985 Oct;4(10):2547–2552. doi: 10.1002/j.1460-2075.1985.tb03969.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chappell M. A., Snyder L. R. Biochemical and physiological correlates of deer mouse alpha-chain hemoglobin polymorphisms. Proc Natl Acad Sci U S A. 1984 Sep;81(17):5484–5488. doi: 10.1073/pnas.81.17.5484. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ewens W. J., Gillespie J. H. Some simulation results for the neutral allele model, with interpretations. Theor Popul Biol. 1974 Aug;6(1):35–57. doi: 10.1016/0040-5809(74)90030-6. [DOI] [PubMed] [Google Scholar]
- Ewens W. J. The sampling theory of selectively neutral alleles. Theor Popul Biol. 1972 Mar;3(1):87–112. doi: 10.1016/0040-5809(72)90035-4. [DOI] [PubMed] [Google Scholar]
- Goodfellow P. N., Payne R. O. Serological studies of Cw1 and Cw3 expressed on the same haplotype. Tissue Antigens. 1978 Apr;11(4):350–356. doi: 10.1111/j.1399-0039.1978.tb01267.x. [DOI] [PubMed] [Google Scholar]
- Hedrick P. W., Thomson G. Evidence for balancing selection at HLA. Genetics. 1983 Jul;104(3):449–456. doi: 10.1093/genetics/104.3.449. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jaraquemada D., Alonso A., Awad J., D'Amaro J., Ollier W., Doyle P., Okoye R. C., Williams E., Festenstein H., Lian F. HLA polymorphisms in a Shanghai Chinese population. Tissue Antigens. 1984 Jan;23(1):23–32. doi: 10.1111/j.1399-0039.1984.tb00004.x. [DOI] [PubMed] [Google Scholar]
- Keith T. P. Frequency Distribution of Esterase-5 Alleles in Two Populations of DROSOPHILA PSEUDOOBSCURA. Genetics. 1983 Sep;105(1):135–155. doi: 10.1093/genetics/105.1.135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Porter R. R. Complement polymorphism, the major histocompatibility complex and associated diseases: a speculation. Mol Biol Med. 1983 Jul;1(1):161–168. [PubMed] [Google Scholar]
- Prevost P., Busson M., Marcelli-Barge A. Distribution of HLA-A,B alleles in 13 panels of blood donors in France. Tissue Antigens. 1984 May;23(5):301–307. doi: 10.1111/j.1399-0039.1984.tb00049.x. [DOI] [PubMed] [Google Scholar]
- Raum D., Awdeh Z., Anderson J., Strong L., Granados J., Teran L., Giblett E., Yunis E. J., Alper C. A. Human C4 haplotypes with duplicated C4A or C4B. Am J Hum Genet. 1984 Jan;36(1):72–79. [PMC free article] [PubMed] [Google Scholar]
- Rittner C., Bertrams J. On the significance of C2, C4, and factor B polymorphisms in disease. Hum Genet. 1981;56(3):235–247. doi: 10.1007/BF00274674. [DOI] [PubMed] [Google Scholar]
- Rittner C., DeMarchi M., Mollenhauer E., Carbonara A. Coeliac disease and C4A*QO: an association secondary to HLA-DR3. Tissue Antigens. 1984 Feb;23(2):130–134. doi: 10.1111/j.1399-0039.1984.tb00022.x. [DOI] [PubMed] [Google Scholar]
- Robson E. B., Lamm L. U. Report of the Committee on the Genetic Constitution of Chromosome 6. Cytogenet Cell Genet. 1984;37(1-4):47–70. doi: 10.1159/000132004. [DOI] [PubMed] [Google Scholar]
- Schendel D. J., O'Neill G. J., Wank R. MHC-linked class III genes. Analysis of C4 gene frequencies, complotypes and associations with distinct HLA haplotypes in German Caucasians. Immunogenetics. 1984;20(1):23–31. doi: 10.1007/BF00373444. [DOI] [PubMed] [Google Scholar]
- Watterson G. A. The homozygosity test of neutrality. Genetics. 1978 Feb;88(2):405–417. doi: 10.1093/genetics/88.2.405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weiss E. H., Golden L., Fahrner K., Mellor A. L., Devlin J. J., Bullman H., Tiddens H., Bud H., Flavell R. A. Organization and evolution of the class I gene family in the major histocompatibility complex of the C57BL/10 mouse. Nature. 1984 Aug 23;310(5979):650–655. doi: 10.1038/310650a0. [DOI] [PubMed] [Google Scholar]
- van Eden W., de Vries R. R., van Rood J. J. HLA and infectious diseases. Prog Clin Biol Res. 1982;103(Pt B):37–54. [PubMed] [Google Scholar]