Showing papers by "Matthias Meyer published in 2013"
TL;DR: The results prove that authentic ancient DNA can be preserved for hundreds of thousand years outside of permafrost and enable the retrieval of phylogenetically informative sequences from samples in which virtually all DNA is diminished to fragments shorter than 50 bp.
Abstract: Although an inverse relationship is expected in ancient DNA samples between the number of surviving DNA fragments and their length, ancient DNA sequencing libraries are strikingly deficient in molecules shorter than 40 bp. We find that a loss of short molecules can occur during DNA extraction and present an improved silica-based extraction protocol that enables their efficient retrieval. In combination with single-stranded DNA library preparation, this method enabled us to reconstruct the mitochondrial genome sequence from a Middle Pleistocene cave bear (Ursus deningeri) bone excavated at Sima de los Huesos in the Sierra de Atapuerca, Spain. Phylogenetic reconstructions indicate that the U. deningeri sequence forms an early diverging sister lineage to all Western European Late Pleistocene cave bears. Our results prove that authentic ancient DNA can be preserved for hundreds of thousand years outside of permafrost. Moreover, the techniques presented enable the retrieval of phylogenetically informative sequences from samples in which virtually all DNA is diminished to fragments shorter than 50 bp.
1,045 citations
TL;DR: The nuclear DNA sequences determined from this early modern human reveal that the Tianyuan individual derived from a population that was ancestral to many present-day Asians and Native Americans but postdated the divergence of Asians from Europeans.
Abstract: Hominins with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 y ago. The genetic relationships between these early modern humans and present-day human populations have not been established. We have extracted DNA from a 40,000-y-old anatomically modern human from Tianyuan Cave outside Beijing, China. Using a highly scalable hybridization enrichment strategy, we determined the DNA sequences of the mitochondrial genome, the entire nonrepetitive portion of chromosome 21 (∼30 Mbp), and over 3,000 polymorphic sites across the nuclear genome of this individual. The nuclear DNA sequences determined from this early modern human reveal that the Tianyuan individual derived from a population that was ancestral to many present-day Asians and Native Americans but postdated the divergence of Asians from Europeans. They also show that this individual carried proportions of DNA variants derived from archaic humans similar to present-day people in mainland Asia.
455 citations
University of Turku1, University of California, Santa Cruz2, Max Planck Society3, University of Tübingen4, University of California, Los Angeles5, Royal Belgian Institute of Natural Sciences6, Russian Academy of Sciences7, Yale University8, Ludwig Maximilian University of Munich9, National Scientific and Technical Research Council10, University of Bonn11, Arizona State University12, Saint Petersburg State University13, Spanish National Research Council14
TL;DR: The findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted, and molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago.
Abstract: The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.
434 citations
TL;DR: This protocol describes a method for converting short single-Stranded and double-stranded DNA into libraries compatible with high-throughput sequencing using Illumina technology, and it is estimated that intact DNA strands are recovered in the library with ∼50% efficiency.
Abstract: This protocol describes a method for converting short single-stranded and double-stranded DNA into libraries compatible with high-throughput sequencing using Illumina technology. This method has primarily been developed to improve sequence retrieval from ancient DNA, but it is also applicable to the sequencing of short or degraded DNA from other sources, and it can also be used for sequencing oligonucleotides. Single-stranded library preparation is performed by ligating a biotinylated adapter oligonucleotide to the 3′ ends of heat-denatured DNA. The resulting strands are then immobilized on streptavidin-coated beads and copied with a polymerase. A second adapter is attached by blunt-end ligation, and library preparation is completed by PCR amplification. We estimate that intact DNA strands are recovered in the library with ∼50% efficiency. Libraries can be generated from up to 12 DNA or oligonucleotide samples in parallel within 2 d.
429 citations
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TL;DR: Under favorable conditions DNA can survive for thousands of years in the remains of dead organisms, but the DNA extracted from such remains is invariably degraded to a small average size by processes that at least partly involve depurination.
Abstract: Under favorable conditions DNA can survive for thousands of years in the remains of dead organisms. The DNA extracted from such remains is invariably degraded to a small average size by processes that at least partly involve depurination. It also contains large amounts of deaminated cytosine residues that are accumulated toward the ends of the molecules, as well as several other lesions that are less well characterized.
313 citations
TL;DR: One major result is a relatively young date for the most recent common ancestor of all living primates which was estimated to 66-69 million years ago, suggesting that the divergence of extant primates started close to the K/T-boundary.
Abstract: Primates, the mammalian order including our own species, comprise 480 species in 78 genera. Thus, they represent the third largest of the 18 orders of eutherian mammals. Although recent phylogenetic studies on primates are increasingly built on molecular datasets, most of these studies have focused on taxonomic subgroups within the order. Complete mitochondrial (mt) genomes have proven to be extremely useful in deciphering within-order relationships even up to deep nodes. Using 454 sequencing, we sequenced 32 new complete mt genomes adding 20 previously not represented genera to the phylogenetic reconstruction of the primate tree. With 13 new sequences, the number of complete mt genomes within the parvorder Platyrrhini was widely extended, resulting in a largely resolved branching pattern among New World monkey families. We added 10 new Strepsirrhini mt genomes to the 15 previously available ones, thus almost doubling the number of mt genomes within this clade. Our data allow precise date estimates of all nodes and offer new insights into primate evolution. One major result is a relatively young date for the most recent common ancestor of all living primates which was estimated to 66-69 million years ago, suggesting that the divergence of extant primates started close to the K/T-boundary. Although some relationships remain unclear, the large number of mt genomes used allowed us to reconstruct a robust primate phylogeny which is largely in agreement with previous publications. Finally, we show that mt genomes are a useful tool for resolving primate phylogenetic relationships on various taxonomic levels.
206 citations
TL;DR: It is found that the derived allele of this site is less efficient than the ancestral allele in activating transcription from a reporter construct, and is a plausible candidate for having caused a recent selective sweep in the FOXP2 gene.
Abstract: The FOXP2 gene is required for normal development of speech and language. By isolating and sequencing FOXP2 genomic DNA fragments from a 49,000-year-old Iberian Neandertal and 50 present-day humans, we have identified substitutions in the gene shared by all or nearly all present-day humansbut absent or polymorphic in Neandertals. One such substitution is localized in intron 8 and affects a binding site for the transcription factor POU3F2, which is highly conserved among vertebrates. We find that the derived allele of this site is less efficient than the ancestral allele in activating transcription from a reporter construct. The derived allele also binds less POU3F2 dimers than POU3F2 monomers compared with the ancestral allele. Because the substitution in the POU3F2 binding site is likely to alter the regulation of FOXP2 expression, and because it is localized in a region of the gene associated with a previously described signal of positive selection, it is a plausible candidate for having caused a recent selective sweep in the FOXP2 gene.
191 citations
TL;DR: Two-dimensional polarization fluorescence imaging of single light harvesting complexes 2 (LH2) of Rps.
Abstract: Two-dimensional polarization fluorescence imaging of single light harvesting complexes 2 (LH2) of Rps. acidophila was carried out to investigate the polarization properties of excitation and fluorescence emission simultaneously, at room temperature. In two separate experiments we excited LH2 with a spectrally narrow laser line matched to the absorption bands of the two chromophore rings, B800 and B850, thereby indirectly and directly triggering fluorescence of the B850 exciton state. A correlation analysis of the polarization modulation depths in excitation and emission for a large number of single complexes was performed. Our results show, in comparison to B800, that the B850 ring is a more isotropic absorber due to the excitonic nature of its excited states. At the same time, we observed a strong tendency for LH2 to emit with dipolar character, from which preferential localization of the emissive exciton, stable for minutes, is inferred. We argue that the observed effects can consistently be explained by static energetic disorder and/or deformation of the complex, with possible involvement of exciton self-trapping.
16 citations