Search

Objectives In 1828, between 8,000 and 15,000 Indians from the Jesuit Missions were brought to Uruguay. There, they were settled in a village, presently named Bella Union, in the northwest corner of the country. According to historic sources, the Indians abandoned the settlement shortly thereafter, with the village subsequently repopulated by “criollos” and immigrants from abroad. As a first approach to reconstruct the genetic history of the population, data about the living population genetic structure will be used. Based on the analysis of the maternal lineages of the inhabitants of Bella Union, and of those from two nearby villages, we expect to partially answer what happened with the first and subsequent inhabitants. Methods We analyzed the maternal lineages of the present inhabitants of Bella Union and neighboring localities through the sequencing of the mitochondrial DNA control region. Results A total of 64.3%, 5.7%, and 30% of the mtDNAs were of Native, African, and West Eurasian origin, respectively. These figures are quite similar to that of the population of Tacuarembo, which is located in northeastern Uruguay. The four main Native American founding haplogroups were detected, with B2 being the most frequent, while some rare subhaplogroups (B2h, C1b2, D1f1) were also found. When compared with other Native American sequences, near- matches most consistently pointed to an Amazonian Indian origin which, when considered with historical evidence, suggested a probable Guarani-Missionary-related origin. Conclusions The data support the existence of a relationship between the historic and present inhabitants of the extreme northwest Uruguay, with a strong contribution of Native Americans to the mitochondrial DNA diversity observed there. Am. J. Hum. Biol. 27:407–416, 2015. © 2014 Wiley Periodicals, Inc.

DNA analyses from forensic casework samples commonly result in complex DNA profiles. Often, these profiles consist of multiple contributors and display multiple stochastic events such as peak height imbalance, allelic or locus drop-out, allelic drop-in, and excessive or indistinguishable stutter. This increased complexity has established a need for more sophisticated methods of DNA mixture interpretation. This study compares the effectiveness of statistical models in the interpretation of artificially created low template two person mixed DNA profiles at varying proportions and template quantities. Two binary models (combined probability of inclusion and random match probability), a semicontinuous (Lab retriever), and continuous model (STRmix™) were compared. Generally, as the sophistication of the models increases, the power of discrimination increases. Differences in discrimination often correlate to each model's ability to use observed data effectively. Binary models require static thresholds resulting in unused data and outliers that may lead to difficult or incorrect interpretation. Semicontinuous and continuous models eliminate the stochastic threshold, however Lab Retriever does not account for stochastic events beyond drop-out and drop-in leading to possible less effective use of the data. STRmix™ incorporates all stochastic events listed above into the calculation making the most effective use of the observed data.

An additional 20 novel mini-short tandem repeat (miniSTR) loci have been developed and characterized beyond the six previously developed by our laboratory for a total of 26 non-CODIS miniSTR markers. These new markers produce short PCR products in the target range of 50-150 base pairs (bp) by moving the primer sequences as close as possible-often directly next to the identified repeat region. These candidate loci were initially screened based on their small amplicon sizes and locations on chromosomes currently unoccupied by the 13 CODIS STR loci or at least 50 Mb away from them on the same chromosome. They were sequenced and evaluated across more than 600 samples, and their population statistics were determined. The heterozygosities of the new loci were compared with those of the 13 CODIS loci and all were found to be comparable. Only five of the new loci had lower values than the CODIS loci; however, all of these were much smaller in size. This data suggests that these 26 miniSTR loci will serve as useful complements to the CODIS loci to aid in the forensic analysis of degraded DNA, as well as missing persons work and parentage testing with limited next-of-kin reference samples.