Search

Y-chromosomal short tandem repeat (Y-STR) markers are used in deficient paternity testing cases, in the detection of male DNA in vaginal smears/swabs collected during investigations of sexual assault cases, and in the identification of missing persons and disaster victims. The increasing relevance of Y-STR DNA typing to forensic practice necessitates evaluation of new markers with high gene diversity and mutation rates in the population. This study presents the work done for the Philippine population. Y-STR haplotypes composed of 36 Y-STR marker units were analyzed in a Filipino population sample of 299 individuals using the PowerPlex® Y23 (PPY23) system and protocols of the International RM Y-STR Study Group that target a set of 13 Rapidly Mutating Y-STR (RM Y-STR) comprising 15 Y-STR marker units. Concordant results were observed at two RM Y-STR marker units, namely DYS570 and DYS576, that are included in both assays. Allele frequency and gene diversity were estimated for each Y-STR marker unit, while haplotype frequency and haplotype diversity were estimated for several combinations of Y-STR marker units. The inclusion of 15 RM Y-STR marker units increased the power of the Filipino Y-STR database to differentiate paternally related males. Comparison of the Filipino Y-STR haplotype data at 36 Y-STR marker units with other populations showed the same level of substructuring for the 21 slow and moderately mutating Y-STR marker units based on geographic locations. This highlights the importance of using an appropriate population database in forensic casework. In addition, the observed high diversity of RM Y-STR haplotypes supports the need for studying diverse group of populations to characterize the extent of RM Y-STR haplotype variation. The Filipino Y-STR haplotype database reported in this study would be of great use for reliable estimation of haplotype frequency for statistical evaluation of forensic caseworks in the Philippines. [ABSTRACT FROM AUTHOR]

Cigarette butts found in crime scenes may be used to identify persons and link them to a crime through DNA prof iling of epithelial cells from saliva stains on these materials. Downstream analysis of cigarette butts poses some challenges because these are often exposed to chemical contaminants and environmental conditions which lead to DNA degradation. In this study, several factors were tested to compare the amount and quality of DNA obtained from cigarette butts extracted using an organic procedure and the QIAamp® DNA Micro Kit (QIAGEN). Results show that exposure to an outside environment had a significant effect on DNA yield and amplif i ability for both extraction procedures. Prolonged storage of cigarette butts of up to six months affected the amount of DNA that can be extracted using the QIAamp® DNA Micro Kit. However, complete DNA prof iles can be generated from cigarette butts stored for six months provided that these samples are stored indoors under controlled temperature conditions and with minimal exposure to contaminants. [ABSTRACT FROM AUTHOR]

The Philippines is a strategic point in the Asia-Pacific region for the study of human diversity, history and origins, as it is a cross-road for human migrations and consequently exhibits enormous ethnolinguistic diversity. Following on a previous in-depth study of Y-chromosome variation, here we provide new insights into the maternal genetic history of Filipino ethnolinguistic groups by surveying complete mitochondrial DNA (mtDNA) genomes from a total of 14 groups (11 groups in this study and 3 groups previously published) including previously published mtDNA hypervariable segment (HVS) data from Filipino regional center groups. Comparison of HVS data indicate genetic differences between ethnolinguistic and regional center groups. The complete mtDNA genomes of 14 ethnolinguistic groups reveal genetic aspects consistent with the Y-chromosome, namely: diversity and heterogeneity of groups, no support for a simple dichotomy between Negrito and non-Negrito groups, and different genetic affinities with Asia-Pacific groups that are both ancient and recent. Although some mtDNA haplogroups can be associated with the Austronesian expansion, there are others that associate with South Asia, Near Oceania and Australia that are consistent with a southern migration route for ethnolinguistic group ancestors into the Asia-Pacific, with a timeline that overlaps with the initial colonization of the Asia-Pacific region, the initial colonization of the Philippines and a possible separate post-colonization migration into the Philippine archipelago. [ABSTRACT FROM AUTHOR]

The Philippines exhibits a rich diversity of people, languages, and culture, including so-called 'Negrito' groups that have for long fascinated anthropologists, yet little is known about their genetic diversity. We report here, a survey of Y-chromosome variation in 390 individuals from 16 Filipino ethnolinguistic groups, including six Negrito groups, from across the archipelago. We find extreme diversity in the Y-chromosome lineages of Filipino groups with heterogeneity seen in both Negrito and non-Negrito groups, which does not support a simple dichotomy of Filipino groups as Negrito vs non-Negrito. Filipino non-recombining region of the human Y chromosome lineages reflect a chronology that extends from after the initial colonization of the Asia-Pacific region, to the time frame of the Austronesian expansion. Filipino groups appear to have diverse genetic affinities with different populations in the Asia-Pacific region. In particular, some Negrito groups are associated with indigenous Australians, with a potential time for the association ranging from the initial colonization of the region to more recent (after colonization) times. Overall, our results indicate extensive heterogeneity contributing to a complex genetic history for Filipino groups, with varying roles for migrations from outside the Philippines, genetic drift, and admixture among neighboring groups. [ABSTRACT FROM AUTHOR]