HLA-B81

HLA-B81 (B81) is an HLA–B serotype. The serotype identifies the HLA-B*8101 and B*8102 (very rare) gene products.[1] B81 is more common in Subsaharan Africa. While there is a B81 serotype, serotyping of B81 is poor when simultaneously tested with anti-B7 or B48 antibodies.[2] (For terminology help see: HLA-serotype tutorial)

major histocompatibility complex (human), class I, B81
Alleles B*8101
Structure (See HLA-B)
Symbol(s) HLA-B
Locus chr.6 6p21.31

Serotype
B81 serotype recognition of Some HLA B*81 allele-group gene products[3]
B*81B81 B7Sample
allele%%size (N)
*8101876657

The serotype recognition of B*8101 is poor and is best identified by genetic techniques such as SSP-PCR and gene sequencing.

Allele frequencies
HLA B*8101 frequencies
freq
[4]Population(%)
Luo (Kenya)6.2
Yaoundé (Cameroon)4.4
Shona (Harare, Zimbabwe)4.0
Nandi (Kenya)4.0
Tswana (South Africa)3.7
Natal Zulu (South African)3.5
Baloch (Iran)3.5
Kenya2.8
Pazeh (Taiwan)2.7
Lusaka (Zambia)2.3
Bakola Pygmy (Cameroon)2.0
Beti (Cameroon)1.7
Oman1.3
Bamileke (Cameroon )1.3
United Arab Emirates1.1
Southern Portugal1.0
Kampala (Uganda)0.9
Sudanese0.5
Delhi (India)0.5
Brazil Parana Mulatto0.5
Romanian0.3
Chinese (Hong Kong, China)0.2
Shijiazhuang Tianjian (Beijing, China)0.2
South Korea0.1
Regions of Africa with Higher B81 frequencies(Red-Orange)

HLA-B81 corresponds to a single allele B*8101. There are no characterized haplotypes of this allele that span multiple regions, though rare haplotypes certainly exist. The frequency in Kenya, Zimbabwe and Cameroon suggest that B81 probably expanded from core groups of Africans in Tanzania, Zambia or the Congo but with a limited spread due to its initial low frequency.

gollark: I don't think this is true, except in a very broadly defined sense.
gollark: If *evolution*... well, "attempts" would be anthropomorphizing it... to cross said chasm, all it can do is just throw broken ones at it repeatedly with no understanding, and select for better ones until one actually sticks.
gollark: If I want to cross a chasm with a bridge, or something, I can draw on my limited knowledge of physics and materials science and whatever and put together a somewhat sensible prototype, then make inferences from what happens to it, and get something working out.
gollark: No. We can reason about problems in various ways. So can some animals.
gollark: It doesn't have its own will. It's a giant non-agent mess driven by tons of interacting blind optimization processes.

References
  1. Marsh, S. G.; Albert, E. D.; Bodmer, W. F.; Bontrop, R. E.; Dupont, B.; Erlich, H. A.; Fernández-Viña, M.; Geraghty, D. E.; Holdsworth, R.; Hurley, C. K.; Lau, M.; Lee, K. W.; Mach, B.; Maiers, M.; Mayr, W. R.; Müller, C. R.; Parham, P.; Petersdorf, E. W.; Sasazuki, T.; Strominger, J. L.; Svejgaard, A.; Terasaki, P. I.; Tiercy, J. M.; Trowsdale, J. (2010). "Nomenclature for factors of the HLA system, 2010". Tissue Antigens. 75 (4): 291–455. doi:10.1111/j.1399-0039.2010.01466.x. PMC 2848993. PMID 20356336.
  2. Ellexson ME, Zhang G, Stewart D, et al. (1995). "Nucleotide sequence analysis of HLA-B*1523 and B*8101. Dominant alpha-helical motifs produce complex serologic recognition patterns for the HLA-B"DT" and HLA-B"NM5" antigens". Hum. Immunol. 44 (2): 103–10. doi:10.1016/0198-8859(95)00082-F. PMID 8847228.
  3. derived from IMGT/HLA
  4. Middleton D, Menchaca L, Rood H, Komerofsky R (2003). "New allele frequency database: http://www.allelefrequencies.net". Tissue Antigens. 61 (5): 403–7. doi:10.1034/j.1399-0039.2003.00062.x. PMID 12753660. External link in |title= (help)
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