TY - JOUR
T1 - High variability of TLR4 gene in different ethnic groups in Iran
AU - Ioana, Mihai
AU - Ferwerda, Bart
AU - Farjadian, Shirin
AU - Ioana, Luiza
AU - Ghaderi, Abbas
AU - Oosting, Marije
AU - Joosten, Leo A.B.
AU - Van Der Meer, Jos W.M.
AU - Romeo, Giovanni
AU - Luiselli, Donata
AU - Dediu, Dan
AU - Netea, Mihai G.
N1 - Funding Information: M.I. was supported by the Sectoral Operational Programme Human Resources Development (SOP HRD), financed from the European Social Fund and by the Romanian Government under the contract number POSDRU/89/1.5/S/64109. B.F. was supported by a Rubicon Grant of the Netherlands Organization for Scientific Research (NWO). M.G.N. was supported by a Vici Grant of the Netherlands Organization for Scientific Research.
PY - 2012/6
Y1 - 2012/6
N2 - Infectious diseases exert a constant evolutionary pressure on the innate immunity genes. TLR4, an important member of the TLR family, specifically recognizes conserved structures of various infectious pathogens. Two functional TLR4 polymorphisms, Asp299Gly and Thr399Ile, modulate innate host defense against infections, and their prevalence between various populations has been proposed to be influenced by local infectious pressures. If this assumption is true, strong local infectious pressures would lead to a homogeneous pattern of these ancient TLR4 polymorphisms in geographically-close populations, while a weak selection or genetic drift may result in a diverse pattern. We evaluated TLR4 polymorphisms in 15 ethnic groups in Iran, to assess whether infections exerted selective pressures on different haplotypes containing these variants. The Iranian subpopulations displayed a heterogeneous pattern of TLR4 polymorphisms, comprising various percentages of Asp299Gly and Thr399Ile, alone or in combination. The Iranian sample, as a whole, showed an intermediate mixed pattern when compared with commonly-found patterns in Africa, Europe, Eastern Asia and the Americas. These findings suggest a weak, or absent, selection pressure on TLR4 polymorphisms in the Middle-East that does not support the assumption of an important role of these polymorphisms in the host defense against local pathogens.
AB - Infectious diseases exert a constant evolutionary pressure on the innate immunity genes. TLR4, an important member of the TLR family, specifically recognizes conserved structures of various infectious pathogens. Two functional TLR4 polymorphisms, Asp299Gly and Thr399Ile, modulate innate host defense against infections, and their prevalence between various populations has been proposed to be influenced by local infectious pressures. If this assumption is true, strong local infectious pressures would lead to a homogeneous pattern of these ancient TLR4 polymorphisms in geographically-close populations, while a weak selection or genetic drift may result in a diverse pattern. We evaluated TLR4 polymorphisms in 15 ethnic groups in Iran, to assess whether infections exerted selective pressures on different haplotypes containing these variants. The Iranian subpopulations displayed a heterogeneous pattern of TLR4 polymorphisms, comprising various percentages of Asp299Gly and Thr399Ile, alone or in combination. The Iranian sample, as a whole, showed an intermediate mixed pattern when compared with commonly-found patterns in Africa, Europe, Eastern Asia and the Americas. These findings suggest a weak, or absent, selection pressure on TLR4 polymorphisms in the Middle-East that does not support the assumption of an important role of these polymorphisms in the host defense against local pathogens.
KW - Asp299Gly and Thr399Ile polymorphisms
KW - Iran
KW - Pattern recognition receptors
KW - TLR4
KW - genetic drift
UR - http://www.scopus.com/inward/record.url?scp=84861802778&partnerID=8YFLogxK
U2 - https://doi.org/10.1177/1753425911423043
DO - https://doi.org/10.1177/1753425911423043
M3 - Article
C2 - 21994256
SN - 1753-4259
VL - 18
SP - 492
EP - 502
JO - Innate immunity
JF - Innate immunity
IS - 3
ER -