Abstract – Non-European ancestries remain largely underrepresented in genomic studies, and the disparity undermines genetic discovery efforts. To bridge this gap, we performed genome-wide genotyping and exome sequencing on over 140,000 participants from the Mexico City Prospective Study (MCOS) – the largest blood-based prospective study in Latin America. Leveraging these datasets in combination with the whole-genome sequencing on a subset of 9,950 selected individuals, we characterised genetic variation in the cohort and identified over 31 million variants not previously reported, including 1.4 million coding variants. Identity-by-decent (IBD) estimation resolved extensive family networks and admixture analysis indicated that ancestries from Mesoamerican Indigenous populations in central, southern and south-eastern Mexico are largely represented in MCPS. We estimated ancestry-specific allele frequencies at 142 million genomic variants, with an effective sample size of 91,856 for Indigenous American ancestry at some variants, all available through a public browser. Moreover, we demonstrate that genetic variation within MCPS can improve genotype imputation and polygenic prediction in individuals of Mexican-decent.

Bio: Dr. Jason Torres is the genetic epidemiologist lead for the Mexico City Prospective Study. He completed his PhD in Molecular Metabolism at the University of Chicago where he investigated the genetic basis of type 2 diabetes (T2D) under the supervision of Prof. Nancy Cox. As a post-doc at the Wellcome Centre for Human Genetics, Jason worked with Prof Mark McCarthy to elucidate regulatory mechanisms at fine-mapped T2D loci by integrating molecular epigenomes in human pancreatic islet cells. In 2020, Jason joined the Clinical Trials Service Unit and Epidemiological Studies Unit within Oxford Population Health (OxPop) where he leads genetic analysis of cardiometabolic traits as part of the MCPS Study Group.
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As a reminder, the gen)omics seminar series runs every other Thursday morning and is intended to increase interaction between individuals working in genomics across Oxford. We encourage in-person attendance where possible. There is time for discussion over, tea, coffee and pastries after the talks.

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Please note that these meetings are closed meetings and only open to members of the University of Oxford to encourage sharing of new and unpublished data. Please respect our speakers and do not share the link with anyone outside of the university. The aim of these seminars is to increase interaction between people working in Genomics across the University so we encourage in person attendance wherever possible.

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