Amylase gene copy number polymorphism in ethnically admixed sample from Brazil. T. Lins1, D. Jimenez2, P. Taveira2, R. Pereira1,2 1) Patologia Molecular, Universidade de Brasilia, Brasilia, DF, Brazil; 2) Ciencias Genomicas e Biotecnologia, Universidade Catolica de Brasilia, Brasilia, DF, Brazil.
Salivary amylase gene (AMY1) copy number variation (CNV) represent a significant variation among individuals and evolved independently in different human population groups worldwide. The AMY1 genetic variation seems to be related with eating habits and dietary consumption of starch as the AMY1 gene copy number, the concentration and activity of salivary amylase enzyme are positively correlated to the starch content diet (high or low starch diet). Therefore, it is necessary to understand the distribution of CNV within and between populations, especially those with admixed ancestry, such as the Brazilians. The aim of the study was to investigate the variability of the AMY1 gene in a sample of 96 Brazilian individuals previously classified by genetic ancestry informative markers. The polymorphism was investigated by real-time qPCR using Taqman assay (Applied Biosystems, Foster city, CA). The mean AMY1 copy number was 2.8 with a range of 1 to 8 copies. The major copy number was identified for 2 copies (47.9%), followed by 3 copies (20.8%) and 4 copies (18.8%). Mean distribution standard deviation of ancestry according to European, African and Native American proportion was, respectively, 0.702 0.232, 0.189 0.158 and 0.109 0.147, for overall sample. A T-test was performed to compare estimated genomic ancestry proportion among 2 copies and gain of copies (3 copies), but no statistical correlation was observed (p = 0.449; 0.494; 0.412, respectively). Despite the low copy number compared to other worldwide populations, the correlation of the polymorphisms with other phenotypic differences must be investigated, such as salivary amylase enzyme concentration and activity, as well as the nutritional status and starch content diet. Since the AMY1 is highly variable, an increased number of individuals in the Brazilian population should be further evaluated to screen a wider range of variation. The results provided an overview of the corresponding frequency of AMY1 gene copy number variation in a sample of the Brazilian population serving as reference for further population and nutrigenomic studies.
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