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Identity by Descent (IBD)

Definition
AI-generated

Two alleles are identical by descent (IBD) if they descend from the same ancestral chromosome segment without an intervening recombination.

Topics
Population genetics
Related
Haplotype Identity by State (IBS) Kinship Coefficient

Why it matters in GWAS

IBD underpins kinship estimation, cryptic relatedness detection, and family-based association tests; long shared IBD segments also support haplotype-based phasing and imputation.

Example usage

"We used segments of IBD > 7 cM to flag second-degree or closer pairs."

Haplotype Identity by State (IBS) Kinship Coefficient Relatedness Relatedness and Sample Structure
Related-term network

Click any node to open that term page.

Node order. The current term is first. Next come every page linked from Related terms, in the same top-to-bottom order as that list. Then new terms appear in two-hop layers: for each of those direct neighbors (in that same order), their related terms are appended if not already listed. A third pass does the same for two-hop nodes. The walk stops when a fixed maximum number of nodes is reached.

References

← International Classification of Diseases Code (ICD) Identity by State (IBS) →

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