A novel polymorphic Alu insertion embedded in a LINE 1 retrotransposon in the human X chromosome (DXS225): identification and worldwide population study.
We describe a novel polymorphic Alu insertion (DXS225) on the human X chromosome (Xq21.3) embedded into an L1 retrotransposon. The DXS225 polymorphism was genotyped in 684 males from the CEPH Human Genome Diversity Panel. This insertion was found in all regions of the globe, suggesting that it took place before modern humans spread from Africa ca. 100,000 years ago. However, only one Amerindian population (Karitiana) showed this insertion allele, which may have been introduced by European admixture. Thus, it appears likely that the Alu insertion was absent from pre-Columbian America. Analysis of molecular variance worldwide demonstrated that 92.2% of the genetic variance was concentrated within populations. DXS225 is flanked by two microsatellites (DXS8114 and DXS1002), which are 86 kb apart and are in very strong linkage disequilibrium. The combination of a unique event polymorphism on the X chromosome in linkage disequilibrium with two rapidly evolving microsatellites should provide a useful tool for studies of human evolution.
Pereira
Rinaldo Wellerson
RW
Laboratório de Genética Bioquímica, ICB, UFMG, Belo Horizonte, MG, Brazil.
Santos
Simone Silva dos
SS
Pena
Sérgio Danilo Junho
SD
D020087:Alu Elements / Q000235:genetics*; D002460:Cell Line; D041321:Chromosomes, Human, X / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population / Q000379:methods*; D015894:Genome, Human; D005838:Genotype; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D044469:Racial Groups / Q000235:genetics; D018626:Retroelements / Q000235:genetics*
D018626:Retroelements