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Approved research

Searching Identity-by-descent segments in biobank-scale cohorts

Principal Investigator: Dr Degui Zhi
Approved Research ID: 24247
Approval date: December 15th 2016

Lay summary

Identical by descent (IBD), shared chromosomal segments among individuals in a population, helps reveal relationships status among study samples. IBD information helps genetic association studies by enabling imputation of genetic variants, refining genetic association testing through explicit adjustment of relatedness. We develop new efficient algorithms for inferring IBD segments, that is feasible for biobank-scale samples. We will apply our methods and existing methods to the UK Biobank genotype data. We will conduct IBD-mapping to identify regions with high levels of IBD among carriers of a disease which may suggest potential causal genes. The proposed research will build a tool that can improve genetic association studies by providing better imputation, detailed modeling of relatedness, and fine-scale IBD sharing among cases. Our efficient algorithm will help unleash the rich genetic sharing information within UK Biobank samples, and increase the impact of this incredible resource for improving the prevention, diagnosis and treatment of illness and the promotion of health throughout society. We will use the UK Biobank genotype data to build an highly-efficient index that enables fast search of IBDs. We will then produce a list of all shared IBD segments over a certain length (e.g., 2cM) among UK Biobank samples. We will validate our results with known pedigree information and other IBD search methods. We will conduct IBD mapping by associating identified IBD sharing against UK Biobank phenotypes. Full cohort.