Browsing by Subject "AIMs"
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Item A Novel Multiplex Assay for an Ancestry-Informative Marker (AIM) Panel of INDELs(2016-05-01) Sturm, Sarah A.; LaRue, Bobby L.; Budowle, Bruce; Krishnamoorthy, Raghu R.The current standard for forensic laboratories in criminal casework is to use Short Tandem Repeat (STR) markers to develop an evidentiary profile. Commercially available STR amplification kits yield amplicons 100 to 500 base pairs (bp) in length. Commonly, forensic DNA samples are highly degraded to approximately 180-200 bps in length, resulting in incomplete STR profiles. Therefore, markers that can be generated with smaller amplicons may be better suited for degraded DNA samples. Additionally, there are cases where no STR match was obtained through a DNA database search and thus no investigative lead is obtained. The bioancestry of a sample donor could aid law enforcement in such cases. A class of markers that could provide investigative value from degraded DNA samples is Ancestry-Informative Marker (AIM) Insertion/Deletions (INDELs). INDELs are polymorphisms that can be amplified from degraded samples due to their smaller amplicon size. AIMs have the ability provide bioancestry information. This project tested the hypothesis that a multiplex PCR-based assay of INDELs can be developed, and subsequently be analyzed by capillary electrophoresis for population identity testing applications. The use of this assay would require no additional tools or machinery than what already is in standard forensic laboratories. To test this hypothesis, a previously developed panel of AIM-INDEL markers was used to develop this multiplex assay.Item Ancestry Informative Markers Tailored to Hispanic Populations(2020-05) Setser, Casandra H.; Cross, Deanna S.; Planz, John V.; Barber, Robert C.; Phillips, Nicole R.; Krishnamoorthy, Raghu R.Hispanic populations are highly heterogeneous despite being grouped together as a conglomerate population; this makes an accurate panel of ancestry informative markers (AIMs) especially important for human identification. In Chapter 2, the Genomic Origins and Admixture in Latinos (GOAL) dataset containing 494,886 SNPs was used for SNP ascertainment. Utilizing a country attributable variant of Wright's FST, 234 SNPs were selected for biogeographic ancestry (BGA) determination by tailoring each SNP to genetic differentiation of specific populations. Accuracy of BGA prediction was tested using multinomial logistic regression (MLR) and as few as 55 SNPs were robust to 90% for all populations studied. The panel of 234 SNPs was compressed by 65.8% to 80 SNPs by decreasing the influence of Honduras and the Dominican Republic SNPs with high country attributable mean FST values in favor of additional SNPs for Colombia, Cuba, and Puerto Rico; this balanced small panel size with classification accuracy. In Chapter 3, the Setser80 Hispanic AIMs panel was tested against the panels of 128 SNPs developed by the Seldin group and 55 SNPs developed by the Kidd group using STRUCTURE, PCA, a naive Bayesian classifier and MLR. In STRUCTURE, the Setser80 was able to distinguish Honduras, the Dominican Republic, and Colombia at K=4, where the Seldin and Kidd panels were optimized at K=3 and distinguished only Honduras and the Dominican Republic; similar results were obtained by PCA. The GOAL dataset was combined with the Admixed American super-population from the 1000 Genomes Project to test the panel on an expanded dataset of seven populations. Overall, the Setser80 had superior results to the Seldin and Kidd panels with 91.5% accuracy by naive Bayesian classifier and 93.2% by MLR. As an indication of its portability, the Setser80 had accuracies of >98% for Peru and >80% for Mexicans living in Los Angeles, which were not involved in SNP ascertainment. Given its accuracy and lack of overlap, the Setser80 may supplement existing panels for more granular Hispanic BGA determination. In Chapter 4, the application of allele frequencies to forensic genetics, genealogy, and clinical genetics are discussed as well as future directions and ethical considerations.