title: Maximum-likelihood estimation of recent shared ancestry (ERSA).
abstract: Accurate estimation of recent shared ancestry is important for genetics, evolution, medicine, conservation biology, and forensics. Established methods estimate kinship accurately for first-degree through third-degree relatives. We demonstrate that chromosomal segments shared by two individuals due to identity by descent (IBD) provide much additional information about shared ancestry. We developed a maximum-likelihood method for the estimation of recent shared ancestry (ERSA) from the number and lengths of IBD segments derived from high-density SNP or whole-genome sequence data. We used ERSA to estimate relationships from SNP genotypes in 169 individuals from three large, well-defined human pedigrees. ERSA is accurate to within one degree of relationship for 97% of first-degree through fifth-degree relatives and 80% of sixth-degree and seventh-degree relatives. We demonstrate that ERSA's statistical power approaches the maximum theoretical limit imposed by the fact that distant relatives frequently share no DNA through a common ancestor. ERSA greatly expands the range of relationships that can be estimated from genetic data and is implemented in a freely available software package.
authors.affiliation: Department of Human Genetics, University of Utah Health Sciences Center, Salt Lake City, Utah 84112, USA.
authors.forename: Chad D
authors.initials: CD
authors.lastname: Huff
authors.forename: David J
authors.initials: DJ
authors.lastname: Witherspoon
authors.forename: Tatum S
authors.initials: TS
authors.lastname: Simonson
authors.forename: Jinchuan
authors.initials: J
authors.lastname: Xing
authors.forename: W Scott
authors.initials: WS
authors.lastname: Watkins
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Zhang
authors.forename: Therese M
authors.initials: TM
authors.lastname: Tuohy
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Neklason
authors.forename: Randall W
authors.initials: RW
authors.lastname: Burt
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Guthery
authors.forename: Scott R
authors.initials: SR
authors.lastname: Woodward
authors.forename: Lynn B
authors.initials: LB
authors.lastname: Jorde
mesh_terms: D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics; D005190:Family; D008040:Genetic Linkage; D006801:Humans; D040582:Inheritance Patterns / Q000235:genetics*; D016013:Likelihood Functions; D008957:Models, Genetic; D015233:Models, Statistical; D020411:Oligonucleotide Array Sequence Analysis; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D012984:Software
chemical_list: D004247:DNA