TIMP2 gene polymorphism as a potential tool to infer Brazilian population origin

Rodrigo Augusto da Silva,¹ André Luis Shinohara,² Denise Carleto Andia,¹ Ariadne Letra,³ Regina Célia Peres,¹ Ana Paula de Souza<sup>1

1</sup>Department of Morphology, Piracicaba Dental School, State University of Campinas, ²Oral Biology Program, Bauru Dental School, State University of São Paulo, São Paulo, Brazil; ³Department of Endodontics and Center for Craniofacial Research, School of Dentistry, University of Texas Health Science Center, Houston, TX, USA

Abstract: Single nucleotide polymorphisms are genome variations that can be used as population-specific markers to infer genetic background and population origin. The Brazilian population is highly admixed due to immigration from several other populations. In particular, the state of São Paulo is recognized for the presence of Japanese individuals who seem likely to have contributed to a substantial proportion of ancestry in the modern Brazilian population. In the present study, we analyzed allele and genotype frequencies and associations of the –418G>C (rs8179090) single nucleotide polymorphism in the TIMP2 gene promoter in Brazilian and Japanese subjects, as well as in Japanese descendants from southeastern Brazil. The allele and genotype frequency analyses among groups demonstrated statistical significance (P<0.001) and the rare C allele was not found in 200 unrelated Brazilian subjects, while its distribution in Japanese individuals and Japanese descendants was 18.7% and 10.3%, respectively. Individuals with the C allele were about 70 times more likely to be Japanese and 41 times more likely to be Japanese descendants compared with Brazilian individuals (odds ratio 69.09, 95% confidence interval 9.35–510 for Japanese; and odds ratio 41.38, 95% confidence interval 4.80–356.15 for Japanese descendants). Taken together, these findings suggest that subjects carrying the C allele, located in the −418G>C single nucleotide polymorphism of the TIMP2 gene, have a high probability of being Japanese or Japanese descendants. In addition to other genetic polymorphisms, the −418G>C TIMP2 polymorphism could be a population marker to assist in predicting Japanese ancestry, both in Japanese individuals and in admixed populations.

Keywords: Brazilian, Japanese, polymorphism, allele, TIMP2