GenoGeographer – A tool for genogeographic inference

TY - JOUR

T1 - GenoGeographer – A tool for genogeographic inference

AU - Tvedebrink, Torben

AU - Eriksen, Poul Svante

AU - Mogensen, Helle Smidt

AU - Morling, Niels

PY - 2017/12/1

Y1 - 2017/12/1

N2 - Ancestry-informative markers (AIMs) are genetic markers that give information about the genogeographic ancestry of individuals. They are used for predicting the genogeographic origin of the investigated individual in crime and identification cases. When exploring the genogeographic origin of an AIMs profile, the likelihoods of the AIMs profile in various populations may be calculated. However, there might not be an apt population in the database of reference populations. The fact that the likelihood ratios (LR) of one population compared to other populations are large does not imply that any of the populations are relevant. This is because that even though the populations might be exclusive, they are not exhaustive in the sense that they cover all possible human populations. To handle this phenomena, we derive a likelihood ratio test (LRT), by which we can judge whether there is at least one population in our reference database that is “sufficiently close” to a profile's “true” genogeographic population. The LRT is a measure of absolute concordance between a profile and a population, rather than a relative measure of the profile's likelihood in two populations (the LR). The LRT is similar to a Fisher's exact test, which means that the varying sample sizes of the reference populations in the database is explicitly included in the calculations, and makes fewer assumptions than for LR calculations. The methodology has been implemented in an free open source interactive platform, GenoGeographer, that enables the forensic geneticist to make explorative analyses, produce various graphical outputs together with evidential weight computations.

AB - Ancestry-informative markers (AIMs) are genetic markers that give information about the genogeographic ancestry of individuals. They are used for predicting the genogeographic origin of the investigated individual in crime and identification cases. When exploring the genogeographic origin of an AIMs profile, the likelihoods of the AIMs profile in various populations may be calculated. However, there might not be an apt population in the database of reference populations. The fact that the likelihood ratios (LR) of one population compared to other populations are large does not imply that any of the populations are relevant. This is because that even though the populations might be exclusive, they are not exhaustive in the sense that they cover all possible human populations. To handle this phenomena, we derive a likelihood ratio test (LRT), by which we can judge whether there is at least one population in our reference database that is “sufficiently close” to a profile's “true” genogeographic population. The LRT is a measure of absolute concordance between a profile and a population, rather than a relative measure of the profile's likelihood in two populations (the LR). The LRT is similar to a Fisher's exact test, which means that the varying sample sizes of the reference populations in the database is explicitly included in the calculations, and makes fewer assumptions than for LR calculations. The methodology has been implemented in an free open source interactive platform, GenoGeographer, that enables the forensic geneticist to make explorative analyses, produce various graphical outputs together with evidential weight computations.

KW - Ancestry informative markers

KW - Fisher's exact test

KW - Forensic genetics

KW - Likelihood ratio test

U2 - 10.1016/j.fsigss.2017.09.196

DO - 10.1016/j.fsigss.2017.09.196

M3 - Journal article

AN - SCOPUS:85030449270

SN - 1875-1768

VL - 6

SP - e463-e465

JO - Forensic Science International: Genetics. Supplement Series

JF - Forensic Science International: Genetics. Supplement Series

ER -