Association between personality traits, eating behaviors, and the genetic polymorphisms FTO-rs9939609 and MAO-A 30 bp u-VNTR with obesity in Mexican Mayan children

IntroductionGenetic variants that control dopamine have been associated with obesity in children through loss of control of satiety and impulses, the manifestation of addictive eating behaviors, and specific personality traits. The variants include FTO-rs9939609 and the MAO-A 30 pb u-VNTR low-transcription alleles (LTA).ObjectiveTo evaluate the genetic association of FTO-rs9939609 and the MAO-A LTA, along with personality traits and eating behavior with obesity in Mayan children from Mexico.MethodsWe cross-sectionally evaluated 186 children (70 with obesity and 116 with normal weight) 6–12 years old from Yucatan, Mexico. Nutritional status was defined with body mass index (BMI) percentiles. Personality traits were evaluated with the Conners and TMCQ tests; eating behavior was evaluated with the CEBQ test. Genotyping with real-time PCR and TaqMan probes was used for FTO-rs9939609, whereas PCR amplification was used for MAO-A u-VNTR.ResultsHigh-intensity pleasure (p = 0.013) and moderate appetite (p = 0.032) differed according to nutritional status. Heterozygous FTO-rs9939609 T/A children showed higher mean scores of low-intensity pleasure (p = 0.002) and moderate appetite (p = 0.027) than homozygous T/T. Hemizygous boys having MAO-A LTA showed significantly higher mean scores of anxiety (p = 0.001) and impulsivity (p = 0.008). In multivariate models, only LTA alleles of MAO-A explained obesity in boys (OR = 4.44; 95% CI = 1.18–16.63).ConclusionIn the present study, MAO-A u-VNTR alleles were associated with obesity in multivariate models only in boys. These alleles might also have a role in personality traits such as anxiety and impulsivity, which secondly contribute to developing obesity in Mayan boys

Demographic History of Indigenous Populations in Mesoamerica Based on mtDNA Sequence Data

The genetic characterization of Native American groups provides insights into their history and demographic events. We sequenced the mitochondrial D-loop region (control region) of 520 samples from eight Mexican indigenous groups. In addition to an analysis of the genetic diversity, structure and genetic relationship between 28 Native American populations, we applied Bayesian skyline methodology for a deeper insight into the history of Mesoamerica. AMOVA tests applying cultural, linguistic and geographic criteria were performed. MDS plots showed a central cluster of Oaxaca and Maya populations, whereas those from the North and West were located on the periphery. Demographic reconstruction indicates higher values of the effective number of breeding females (Nef) in Central Mesoamerica during the Preclassic period, whereas this pattern moves toward the Classic period for groups in the North and West. Conversely, Nef minimum values are distributed either in the Lithic period (i.e. founder effects) or in recent periods (i.e. population declines). The Mesomerican regions showed differences in population fluctuation as indicated by the maximum Inter-Generational Rate (IGRmax): i) Center-South from the lithic period until the Preclassic; ii) West from the beginning of the Preclassic period until early Classic; iii) North characterized by a wide range of temporal variation from the Lithic to the Preclassic. Our findings are consistent with the genetic variations observed between central, South and Southeast Mesoamerica and the North-West region that are related to differences in genetic drift, structure, and temporal survival strategies (agriculture versus hunter-gathering, respectively). Interestingly, although the European contact had a major negative demographic impact, we detect a previous decline in Mesoamerica that had begun a few hundred years before

Skyline plot for the 28 populations grouped in the five cultural regions.

<p>North, West, Central, Oaxaca and Maya.</p

Geographical and cultural information from the 28 Native American populations included in this study.

<p>Geographical and cultural information from the 28 Native American populations included in this study.</p

Hgs frequencies (%) for the eight Native Mexican populations according to the complete mtDNA control region.

<p>Hgs frequencies (%) for the eight Native Mexican populations according to the complete mtDNA control region.</p

Time distribution (bottom) of the maximum (green points) and minimum Nef values (red points) by Mesoamerican periods (top) for populations clustered in cultural areas.

<p>The vertical red stripe indicates periods before 8,000 ybp.</p

Geographical location of the 28 populations included in the study.

<p>Quadrants represent the regions zoomed in the supplementary information based on the cultural areas of Mesoamerica. Populations studied in this paper appear in bold. For abbreviations please check <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131791#pone.0131791.t001" target="_blank">Table 1</a>.</p