Molecular Genetic Analysis Of FUT3 In Sindhi And Punjabi From Pakistan

Background and Objective:The FUT3（Lewis）gene encodes fucosyltransferase Ⅲ which regulates the expression of Lewis blood group antigen.It is highly polymorphic and ethnically specific.To date,Lewis gene data and distribution characteristics have been reported in many countries and races around the world,but such basic data are not available in Pakistan,a multi-ethnic country.Therefore,objective of the study was to perform systematic sequence analysis in coding region of FUT3 by DNA sequencing to investigate the genetic variations of FUT3 and molecular basis of Lewis phenotype in Sindhi and Punjabi populations of Pakistan.Methods:The whole FUT3 coding region（1086bp）was screened for sequence variations by sanger sequencing in two populations,Sindhi（200）and Punjabi（157）from Pakistan.Some haplotypes were determined by molecular cloning technology and allele specific PCR method.The functional significance of several unreported mutations on the encoded enzyme was also predicted by PolyPhen and PROVEAN programs.The Lewis allele frequency of two populations was statistically analyzed.Results:Twenty-three single nucleotide variations including seven unreported mutations were found,and all new missense mutations are present in Lewis-negative alleles confirmed previously;Also identified were eleven novel alleles;Except for wild type allele（Le）,the most common alleles were le^202,314 and le^59,1067 in two populations,but frequency distribution of le^59,1067 in Punjabi population is significantly higher than in Sindh population;The frequency of Lewis-negative phenotype is 11.5%（Sindhi）and 22.93%（Punjabi）.In addition,two missense mutations（G490A and T959C）were predicted to be deleterious on the enzyme activity by software’s assessment.Conclusion:1.Multiple single nucleotide variations and wide variety of alleles including eleven novel alleles were identified,and the two populations,Sindhi and Punjabi,were not previously studied with reference to FUT3.2.Based on the characteristics of allele frequency distribution,we found that there are similarities but micro differences between two populations.3.By comparing with other published population data on FUT3 locus,genetic characters of Sindhi and Punjabi from Pakistan are much more closely related to Sinhalese and Caucasians.