Project description:Six infant human teeth and 112 animal tooth pendants from Borsuka Cave were identified as the oldest burial in Poland. However, uncertainties around the dating and the association of the teeth to the pendants have precluded their association with an Upper Palaeolithic archaeological industry. Using <67 mg per tooth, we combined dating and genetic analyses of two human teeth and six herbivore tooth pendants to address these questions. Our interdisciplinary approach yielded informative results despite limited sampling material, and high levels of degradation and contamination. Our results confirm the Palaeolithic origin of the human remains and herbivore pendants, and permit us to identify the infant as female and discuss the association of the assemblage with different Palaeolithic industries. This study exemplifies the progress that has been made toward minimally destructive methods and the benefits of integrating methods to maximize data retrieval from precious but highly degraded and contaminated prehistoric material.
Project description:The prevailing theory for the molecular basis of evolution involves genetic mutations that ultimately generate the heritable phenotypic variation on which natural selection acts. However, epigenetic transgenerational inheritance of phenotypic variation may also play an important role in evolutionary change. A growing number of studies have demonstrated the presence of epigenetic inheritance in a variety of different organisms that can persist for hundreds of generations. The possibility that epigenetic changes could accumulate over macroevolutionary time has been considered, but not yet seldom been tested empirically. The current study was designed to compare epigenetic changes among several closely related species of Darwin’s finches, a well-known example of adaptive radiation. Erythrocyte DNA was obtained from five species of sympatric Darwin's finches that vary in phylogenetic relatedness. Genome wide alterations in genetic mutations using copy number variation (CNV) were compared to epigenetic alterations associated with differential DNA methylation regions (epimutations). Epimutations were more common than genetic CNV mutations among the five species; furthermore, the number of epimutations increased monotonically with phylogenetic distance. Interestingly, the number of genetic CNV mutations did not consistently increase with phylogenetic distance. The number, chromosomal locations, regional clustering, and lack of overlap of epimutations and genetic mutations suggests that epigenetic changes are distinct and that they correlate with the evolutionary history of Darwin’s finches. The potential functional significance of the epimutations was explored by comparing their locations on the genome to the location of evolutionarily important genes and cellular pathways in birds. Specific epimutations were associated with genes related to the bone morphogenic protein (BMP), toll receptor, and melanogenesis signaling pathways. Species- specific epimutations were significantly over-represented in these pathways. Since environmental factors are known to rapidly alter heritable changes in the epigenome, it is possible that epigenetic changes have played a contributing role in the molecular basis of the evolution of Darwin's finches.
Project description:The molecular basis of evolutionary change is assumed to be genetic variation. However, growing evidence suggests that epigenetic mechanisms, such as DNA methylation, may also be involved in evolutionary change. An important first step in evaluating this hypothesis is to test for the presence of epigenetic variation between natural populations living under different environmental conditions. In the current study we explored variation between populations of Darwin’s finches living in adjacent “urban” and “rural” environments on Santa Cruz Island in the Galápagos. We tested for morphological, genetic, and epigenetic differences between the urban and rural populations of each of two species of ground finches, Geospiza fortis and G. fuliginosa. Using data collected from more than 1000 birds, we found significant morphological differences between populations of G. fortis, but not G. fuliginosa. We did not find genetic differences between populations of either species, based on comparisons of copy number variation (CNV). In contrast, we did find epigenetic differences between the urban and rural populations of both species, based on DNA methylation analysis. We explored genomic features and gene associations of the differentially methylated regions (DMR), as well as their possible functional significance. In summary, our study documents local population epigenetic variation within species of Darwin’s finches.
Project description:Panicum miliaceum L. was domesticated in northern China at least 7000 years ago and was subsequentially adopted in many areas throughout Eurasia. One such locale is Areni-1 an archaeological cave site in Southern Armenia, where vast quantities archaeobotanical material were well preserved via desiccation. The rich botanical material found at Areni-1 includes P. miliaceum grains that were identified morphologically and14C dated to the medieval period (873 ± 36 CE and 1118 ± 35 CE). To investigate the demographic and evolutionary history of the Areni-1 millet, we used ancient DNA extraction, hybridization capture enrichment, and high throughput sequencing to assemble three chloroplast genomes from the medieval grains and then compared these sequences to 50 modern P. miliaceum chloroplast genomes. Overall, the chloroplast genomes contained a low amount of diversity with domesticated accessions separated by a maximum of 5 SNPs and little inference on demography could be made. However, in phylogenies the chloroplast genomes separated into two clades, similar to what has been reported for nuclear DNA from P. miliaceum. The chloroplast genomes of two wild (undomesticated) accessions of P. miliaceum contained a relatively large number of variants, 11 SNPs, not found in the domesticated accessions. These results demonstrate that P. miliaceum grains from archaeological sites can preserve DNA for at least 1000 years and serve as a genetic resource to study the domestication of this cereal crop.
Project description:Regenerating feathers of the Gouldian finches were collected from heads of moulting individuals from an Australian captive population. Affymetrix microarrays were used to examine gene expression differences between black and red morphs.
Project description:Feasting is one of humanity's most universal and unique social behaviors. Although evidence for feasting is common in the early agricultural societies of the Neolithic, evidence in pre-Neolithic contexts is more elusive. We found clear evidence for feasting on wild cattle and tortoises at Hilazon Tachtit cave, a Late Epipaleolithic (12,000 calibrated years B.P.) burial site in Israel. This includes unusually high densities of butchered tortoise and wild cattle remains in two structures, the unique location of the feasting activity in a burial cave, and the manufacture of two structures for burial and related feasting activities. The results indicate that community members coalesced at Hilazon to engage in special rituals to commemorate the burial of the dead and that feasts were central elements in these important events. Feasts likely served important roles in the negotiation and solidification of social relationships, the integration of communities, and the mitigation of scalar stress. These and other social changes in the Natufian period mark significant changes in human social complexity that continued into the Neolithic period. Together, social and economic change signal the very beginning of the agricultural transition.
Project description:Many animals exhibit typical color patterns that have been linked to key adaptive functions, yet the developmental mechanisms establishing these crucial designs remain unclear. Here, we surveyed color distribution in the plumage across a large number of passerine finches. Despite extreme apparent pattern diversity, we identified a small set of conserved color regions whose combinatory association can explain all observed patterns. We found these domains are instructed by signals from embryonic somites and lateral plate mesoderm, and through profiling and comparative analyses, produced a molecular map marking putative color domains in the developing skin. This revealed cryptic pre-patterning common to differently colored species, uncovering a simple molecular landscape underlying extensive color pattern variation.