A likelihood ratio approach for identifying three-quarter siblings in genetic databases.

摘要: The detection of family relationships in genetic databases is interest various scientific disciplines such as epidemiology, population and conservation genetics, forensic science, genealogical research. Nowadays, screening for related individuals forms an important aspect standard quality control procedures. Relatedness research usually based on allele sharing analysis identity by state (IBS) or descent (IBD) alleles. Existing IBS/IBD methods mainly aim to identify first-degree (parent-offspring full siblings) second degree (half-siblings, avuncular, grandparent-grandchild) pairs. Little attention has been paid the in-between first second-degree three-quarter siblings (3/4S) who share fewer alleles than but more relationships. With progressively increasing sample sizes used research, it becomes likely that are present database under study. In this paper, we extend existing likelihood ratio (LR) methodology accurately infer existence 3/4S, distinguishing them from relatives. We use bootstrap confidence intervals express uncertainty LRs. Our proposal accounts linkage disequilibrium (LD) using marker pruning, validate our with a pedigree-based simulation study accounting both LD recombination. An empirical genome-wide array data set GCAT Genomes Life cohort project illustrate method.