51 research outputs found

    Correlating Biological Relationships, Social Inequality, and Population Movement among Prehistoric California Foragers: Ancient Human DNA Analysis from CA-SCL-38 (Yukisma Site)

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    Reconstruction of regional North American prehistory has benefited from the incorporation of ancient DNA evidence. However, few studies focus on intra-site genetic variation, associate these relationships to mortuary assemblages, or link these variables to social ranking. The Late Period (900 BP-250 BP) in the San Francisco Bay area witnessed shifts in settlement patterns that included mortuary treatment distinct from earlier periods. The change in mortuary pattern is interpreted either as a reduction in social inequality, a shift toward corporate group identity based on kinship, or an emergence of a lesser number of differentiated elites with control over high status resources. Mitochondrial DNA (mtDNA) data was collected from 200 individuals from CA-SCL-38 (Yukisma Mound), hereafter referred to as SCL-38 as well as 102 additional burials from 15 other archaeological sites in the region to test for a relationship between direct maternal kinship (i.e., genetic relatedness as revealed by mtDNA), grave goods, and burial patterns. This was ultimately done to determine whether spatial patterns at SCL-38 are associated with the emergence/maintenance of social differentiation and inferred social inequality. These data were additionally used at the inter-site level to explore the hypothesized spread of Penutian populations and to document genetic continuity in the San Francisco Bay area through time. Results indicate that maternal relatedness is not correlated to the spatial distribution of burials within the cemetery. Additionally, no associations are noted between particular mtDNA haplotypes and burials with high quantity or diversity of grave goods. Thus, the overall placement of burials at SCL-38 are random with respect to direct maternal relationships. However, regardless of mortuary assembleges, there are some subgroupings within the cemetery of individuals related at the maternal level. The heterogenous distribution of mtDNA lineages across the spatial extent of the site may instead reflect its use as a regional cemetery for select, perhaps wealthy elite, individuals who originated from the surrounding Bay area. It remains possible that patterning along the paternal line or the lack of temporal refinement is confounding other underlying genetic structure. Across the landscape, however, mtDNA lineages are identified that correspond with the hypothesized influx of Proto-Utian (Penutian) speakers into the San Francisco Bay area by the end of the Early Period and beginning of the Middle Period. Additonal haplotypes are also identified that are probably older than 7,000 BP in the region, most likely representing maternal lineages orignally belonging to ancestral Hokan speakers. Most mtDNA haplotypes discussed represent at least 2,000 years of genetic continuity in the region

    How Much DNA is Lost? Measuring DNA Loss of STR Length Fragments Targeted by the PowerPlex 16® System Using the Qiagen MinElute Purification Kit

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    The success in recovering genetic profiles from aged and degraded biological samples is diminished by fundamental aspects of DNA extraction, as well as its long-term preservation that are not well understood. While numerous studies have been conducted to determine whether one extraction method performed superior to others, nearly all of them were initiated with no knowledge of the actual starting DNA quantity in the samples prior to extraction, so they ultimately compared the outcome of all methods relative to the best. Using quantitative PCR (qPCR) to estimate the copy count of synthetic standards before (i.e., “copies in”) and after (i.e., “copies out”) purification by the Qiagen MinElute PCR Purification Kit, we documented DNA loss within a pool of 16 different sized fragments ranging from 106–409 base pairs (bps) in length, corresponding to those targeted by the Promega PowerPlex 16® System. Across all standards starting from 10^4 to 10^7 copies/μL, loss averaged between 21.75% to 60.56% (mean 39.03%), which is not congruent with Qiagen’s claim that 80% of 70 bp to 4 kb fragments are retained using this product (i.e., 20% loss). Our study also found no clear relationship between neither DNA strand length and retention, nor starting copy number and retention. This suggests that there is no molecule bias across the MinElute column membrane and highlights the need for manufacturers to clearly and accurately describe how their claims are made, and should also encourage researchers to document DNA retention efficiencies of their own methods and protocols. Understanding how and where to reduce loss of molecules during extraction and purification will serve to generate clearer and more accurate data, which will enhance the utility of ancient and low copy number DNA as a tool for closing forensic cases or in reconstructing the evolutionary history of humans and other organisms

    The Earliest Farmers of Northwest China Exploited Grain-fed Pheasants not Chickens

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    Though chickens (Gallus gallus domesticus) are globally ubiquitous today, the timing, location, and manner of their domestication is contentious. Until recently, archaeologists placed the origin of the domestic chicken in northern China, perhaps as early as 8,000 years ago. Such evidence however complicates our understanding of how the chicken was domesticated because its wild progenitor – the red jungle fowl (Gallus gallus) – lives in tropical ecosystems and does not exist in northern China today or in the recent past. Increasingly, multiple lines of evidence suggest that many of the archaeological bird remains underlying this northern origins hypothesis have been misidentified. Here we analyze the mitochondrial DNA of some of the earliest purported chickens from the Dadiwan site in northern China and conclude that they are pheasants (Phasianus colchicus). Curiously, stable isotope values from the same birds reveal that their diet was heavy in agricultural products (namely millet), meaning that they lived adjacent to or among some of the earliest farming communities in East Asia. We suggest that the exploitation of these baited birds was an important adaptation for early farmers in China’s arid north, and that management practices like these likely played a role in the domestication of animals – including the chicken – in similar contexts throughout the region.The original isotopic analyses of these remains were conducted in collaboration with Seth Newsome (then at the Carnegie Institution of Washington) and Chen Fahu (Lanzhou University), with funding from the Wenner-Gren Foundation (awarded to L.B.). The University of Oklahoma provided funding for all molecular analyses (through B.M.K.). Open Access fees paid for in whole or in part by the University of Oklahoma LibrariesYe

    Genetic Diversity and Relationships of Tlingit Moieties

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    The Tlingit from Southeast Alaska belong to the Northwest Coast cultural tradition, which is defined by regionally shared sociocultural practices. A distinctive feature of Tlingit social organization is the matrilineal exogamous marriage system among clans from two opposite moieties: the Raven/Crow and Eagle/Wolf. Clan and moiety membership are determined by matrilineal descent, and previous genetic studies of Northwest Coast populations have shown that there is a relationship between clan membership and genetic variation of matrilines and patrilines. To further understand this association, mitochondrial DNA (mtDNA) sequences from the Tlingit (n=154) are examined. By comparing mtDNA with moiety membership information, we explore the impact of marriage traditions among the Tlingit with their observable genetic variation. At the genetic level, the results support cultural persistence of Tlingit maternal moiety identity despite the negative impacts of European colonization. Our study additionally illustrates the relevance of data derived from Tlingit oral traditions to test hypotheses about population history on the Northwest Coast

    To Clone or Not To Clone: Method Analysis for Retrieving Consensus Sequences In Ancient DNA Samples

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    The challenges associated with the retrieval and authentication of ancient DNA (aDNA) evidence are principally due to post-mortem damage which makes ancient samples particularly prone to contamination from “modern” DNA sources. The necessity for authentication of results has led many aDNA researchers to adopt methods considered to be “gold standards” in the field, including cloning aDNA amplicons as opposed to directly sequencing them. However, no standardized protocol has emerged regarding the necessary number of clones to sequence, how a consensus sequence is most appropriately derived, or how results should be reported in the literature. In addition, there has been no systematic demonstration of the degree to which direct sequences are affected by damage or whether direct sequencing would provide disparate results from a consensus of clones

    Pleiotropic effects of genetic risk variants for other cancers on colorectal cancer risk: PAGE, GECCO and CCFR consortia

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    Genome-wide association studies (GWAS) have identified a large number of single nucleotide polymorphisms (SNPs) associated with a wide array of cancer sites. Several of these variants demonstrate associations with multiple cancers, suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesized that SNPs previously associated with other cancers may additionally be associated with colorectal cancer. In a large-scale study, we examined 171 SNPs previously associated with 18 different cancers for their associations with colorectal cancer

    New genetic loci link adipose and insulin biology to body fat distribution.

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    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

    Proceedings of the 3rd Biennial Conference of the Society for Implementation Research Collaboration (SIRC) 2015: advancing efficient methodologies through community partnerships and team science

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    It is well documented that the majority of adults, children and families in need of evidence-based behavioral health interventionsi do not receive them [1, 2] and that few robust empirically supported methods for implementing evidence-based practices (EBPs) exist. The Society for Implementation Research Collaboration (SIRC) represents a burgeoning effort to advance the innovation and rigor of implementation research and is uniquely focused on bringing together researchers and stakeholders committed to evaluating the implementation of complex evidence-based behavioral health interventions. Through its diverse activities and membership, SIRC aims to foster the promise of implementation research to better serve the behavioral health needs of the population by identifying rigorous, relevant, and efficient strategies that successfully transfer scientific evidence to clinical knowledge for use in real world settings [3]. SIRC began as a National Institute of Mental Health (NIMH)-funded conference series in 2010 (previously titled the “Seattle Implementation Research Conference”; $150,000 USD for 3 conferences in 2011, 2013, and 2015) with the recognition that there were multiple researchers and stakeholdersi working in parallel on innovative implementation science projects in behavioral health, but that formal channels for communicating and collaborating with one another were relatively unavailable. There was a significant need for a forum within which implementation researchers and stakeholders could learn from one another, refine approaches to science and practice, and develop an implementation research agenda using common measures, methods, and research principles to improve both the frequency and quality with which behavioral health treatment implementation is evaluated. SIRC’s membership growth is a testament to this identified need with more than 1000 members from 2011 to the present.ii SIRC’s primary objectives are to: (1) foster communication and collaboration across diverse groups, including implementation researchers, intermediariesi, as well as community stakeholders (SIRC uses the term “EBP champions” for these groups) – and to do so across multiple career levels (e.g., students, early career faculty, established investigators); and (2) enhance and disseminate rigorous measures and methodologies for implementing EBPs and evaluating EBP implementation efforts. These objectives are well aligned with Glasgow and colleagues’ [4] five core tenets deemed critical for advancing implementation science: collaboration, efficiency and speed, rigor and relevance, improved capacity, and cumulative knowledge. SIRC advances these objectives and tenets through in-person conferences, which bring together multidisciplinary implementation researchers and those implementing evidence-based behavioral health interventions in the community to share their work and create professional connections and collaborations
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