First-degree familial relationships coincidences in a population database of Jujuy (Argentina) compared with simulated populations

JUAN JOSE MARTINEZ; MARCOS FELIPE TULA MOLINA; LUIS ADRIÁN SÁNCHEZ; MARÍA ÍNES DEUS; MARÍA ISABEL RAMELLA; GLADYS BEATRÍZ MAURÍN; GUSTAVO MARTÍNEZ; ARIEL CHERNOMORETZ; MARÍA SOLEDAD ESCOBAR; GUSTAVO SIBILLA; MARÍA CECILIA MIOZZO

Praga

Congreso; 28th International Congress of International Society for Forensic Genetics; 2019

the Czechoslovak Society for Forensic Genetics and C-IN

Jujuy, a province from Northwestern Argentina, has a population with great input of Native American gene pool, together with European and African contribution. For forensic purposes a frequency population database was built selecting 500 non related individuals from Jujuy province and genotyping them with 21 autosomal STRs from the kit GlobalFiler. The genetic profiles were incorporated in GENis (a software developed in Argentina for storage and comparison of DNA profiles) to corroborate there were no matches in high stringency. After this confirmation, we run a searching strategy with low stringency, which is used to find parent-child relationships. Four (4) adventitious matches were found. To investigate if this result was due to a specific population characteristic of Jujuy, 100 populations, with 500 random genetic profiles each one, were simulated using Jujuy allele frequencies. For this purpose the forensim R package was used and every population was analyzed with GENis with low stringency. The coincidences for these populations were in average 1.74 (95% CI: 1.5-2), even though 4 matches were found in 5 populations, 5 matches in 2 and there was one population with 6 matches. There were no significant differences between Jujuy and the simulated populations, so we disregard that adventitious matches are because of a specific Jujuy population characteristic. It is known that the number of adventitious matches increases when you go down with stringency in DNA databases, but analyzing a high number of autosomal STRs, the 4 matches were unexpected. So, care should be taken with first-degree relationships searches even with high number of markers. LR calculations and complementary studies (like Y chromosome and mitochondrial DNA) must be done in this kind of searches.