Identical by state
Identical by state or identity by state (IBS) is a term used in genetics to describe two identical alleles or two identical segments or sequences of DNA. The terms identical by type or identity by type (IBT) are sometimes also used. In genetic genealogy the term IBS is generally used to describe segments which are not identical by descent and therefore do not share a recent common ancestor. IBS is also used in genetic genealogy to describe small IBD segments which are shared by many people both within and between populations and which have no genealogical relevance.
- FTDNA definition of identical by state Family Tree DNA Learning Center
- Wheaton K. atDNA matches. Lesson 9 in the series "Beginners' Guide to Genetic Genealogy", Wheaton Surname Resources website, 2013.
- Cooper K. The ABCs of DNA - IBD vs IBS vs mIBC Kitty Cooper's DNA Genealogy blog, 30 January 2012.
- Turner A. "Satiable Curiosity: Identity Crisis: Identical by State or Identical by Descent?" Journal of Genetic Genealogy Fall 2011, Volume 7.