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 -
