<p> When an evidential DNA profile does not match identified suspects or profiles from available databases, further DNA analyses targeted at inferring the possible ancestral origin and phenotypic characteristics of the perpetrator could yield valuable information. Single Nucleotide Polymorphisms (SNPs), the most common form of genetic polymorphisms, have alleles associated with specific populations and/or correlated to physical characteristics. With this research, single base primer extension (SBE) technology was used to develop a 50 SNP assay designed to predict ancestry among the primary U.S. populations (African American, East Asian, European, and Hispanic/Native American), as well as pigmentation phenotype. The assay has been optimized to a sensitivity level comparable to current forensic DNA analyses, and has shown robust performance on forensic-type samples. In addition, three prediction models were developed and evaluated for ancestry in the U.S. population, and two models were compared for eye color prediction, with the best models and interpretation guidelines yielding correct information for 98% and 100% of samples, respectively. Also, because data from additional DNA markers (STR, mitochondrial and/or Y chromosome DNA) may be available for a forensic evidence sample, the possibility of including this data in the ancestry prediction was evaluated, resulting in an improved prediction with the inclusion of STR data and decreased performance when including mitochondrial or Y chromosome data. Lastly, the possibility of using next-generation sequencing (NGS) to genotype forensic STRs (and thus, the possibility of a multimarker multiplex incorporating all forensic markers) was evaluated on a new platform, with results showing the technology incapable of meeting the needs of the forensic community at this time.</p>

Human populations in Africa have high levels of genetic, cultural and linguistic diversity. Despite this, only a small proportion of African populations have been studied from a genetics perspective. There is a particular dearth of information for Southern Africa, even though this region is one of the few places where hunter-gatherer, pastoralist and farmer populations remain, and where interaction between these groups can be studied. This thesis analyses novel populations from Lesotho, Namibia and South Africa, for both maternal and paternal markers, in order to provide a more accurate understanding of the history of this region. Analysis of biodemographic data for these populations highlights signatures of specific cultural traits. Interestingly, contrary to expectations, results indicate that in the patrilocal Basotho there are no differences in within and between area mtDNA and NRY variation, despite observations of a higher female than male migration rate. Females move preferentially at shorter distances than males, minimising the impact of the higher female migration rate. Further analysis of the Southern African samples indicates that the genetic composition of these populations is different to previously studied populations from Sub-Saharan Africa. Notably, there is a significantly higher maternal hunter-gatherer component, potentially as a result of an archeologically defined static frontier which existed along the Maloti/Drakensberg escarpment. Analysis of Namibian samples provides additional information about the history of populations with different lifestyles in the region, with support for a link between Southern Africa pastoralists and East Africa, while other Namibian populations appear genetically different from previously studied populations. Overall, this work demonstrates the diversity of populations in Southern Africa, improves understanding of the history of this region, and also emphasises the value of having access to geographically and ethnically well-defined samples.

No description available.

The evolutionary history of H. neanderthalensis, interwoven with that of H. sapiens, has always fascinated the scientific world. Recent adavncess in paleogenetics shedds new light on the phylogenetic relationship between Neandertals and modern humans. The studies developed in this thesis intend principally to control the contaminants through the development of an anti-contamination protocol for decreasing the human contamination in pre-laboratory phases. We designed a PCR-based method specific for reducing human contamination during the laboratory analysis, and we analyzed the fragmentation pattern of the ancient sequences by massively parallel sequencing technologies. Furthermore, we studied two nuclear genes, TAS2R38 -associated to bitter taste perception- and ABO blood group system –involved in natural immunity- that provide specific information on aspects of the Neanderthal phenotype and adaptation. / La historia evolutiva d’H. neanderthalensis, imbricada amb la d’H. sapiens, ha fascinat sempre el món científic. Avenços recents en paleogenètica aporten una nova llum sobre la rel•lació filogenètica entre els neandertals i els humans moderns. Els treballs d’aquesta tesi intenten principalment controlar els contaminants mitjançant el desenvolupament d’un protocol d’anti-contaminació que disminueixi la contaminació humana de les mostres en la fase de pre-laboratori. Hem desenvolupat un mètode basat en la PCR específic per a reduïr els contaminants humans durant l’anàlisi en el laboratori, i hem analitzat el patró de fragmentació de les seqüències antigues amb tècniques de seqüenciació massiva en paral•lel. A més a més, hem estudiat dos gens nuclears, el TAS2R38 –associat a la percepció del gust amarg- i el grup sanguini ABO –implicat en la immunitat natural- que proporcionen informació específca sobre aspectes del fenotip i de les adaptacions dels neandertals.