Johannes Krause | Eberhard Karls Universität Tübingen (original) (raw)

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Papers by Johannes Krause

Mitochondrial DNA sequences were identified amongst all sequence reads using the following criter... more Mitochondrial DNA sequences were identified amongst all sequence reads using the following criteria: First, each sequence was required to be >30 nucleotides long and show >90% identity to the reference human mtDNA sequence (GI:17981852) or against a version of this sequence where the HVRI had been substituted for the Vindija-80 HVRI when compared by megablast (-b10 -v 10 -U F -I T -e 0.001 -F F -a 1 -D 2 -W 16). Second, alignment bit scores were required to be at least as high as the best scoring alignment against the human nuclear genome. All such mtDNA fragment were then semi-globally aligned to the reference human mtDNA sequence and merged using the human mtDNA to order and orient each mtDNA fragment.

Nature, 2010

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequen... more Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population `Denisovans' and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.

Science, 2010

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Eu... more Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

BMC Evolutionary Biology, 2008

The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibilit... more The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibility to different pathogens. It has been estimated that all genetic variation underlying the human ABO alleles appeared along the human lineage, after the divergence from the chimpanzee lineage. A paleogenetic analysis of the ABO blood group gene in Neandertals allows us to directly test for the presence of the ABO alleles in these extinct humans.

Nature, 2011

Technological advances in DNA recovery and sequencing have drastically expanded the scope of gene... more Technological advances in DNA recovery and sequencing have drastically expanded the scope of genetic analyses of ancient specimens to the extent that full genomic investigations are now feasible and are quickly becoming standard. This trend has important implications for infectious disease research because genomic data from ancient microbes may help to elucidate mechanisms of pathogen evolution and adaptation for emerging and re-emerging infections. Here we report a reconstructed ancient genome of Yersinia pestis at 30-fold average coverage from Black Death victims securely dated to episodes of pestilence-associated mortality in London, England, 1348-1350. Genetic architecture and phylogenetic analysis indicate that the ancient organism is ancestral to most extant strains and sits very close to the ancestral node of all Y. pestis commonly associated with human infection. Temporal estimates suggest that the Black Death of 1347-1351 was the main historical event responsible for the introduction and widespread dissemination of the ancestor to all currently circulating Y. pestis strains pathogenic to humans, and further indicates that contemporary Y. pestis epidemics have their origins in the medieval era. Comparisons against modern genomes reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype. These findings support the notion that factors other than microbial genetics, such as environment, vector dynamics and host susceptibility, should be at the forefront of epidemiological discussions regarding emerging Y. pestis infections.

BMC Evolutionary Biology, 2008

Background: Despite being one of the most studied families within the Carnivora, the phylogenetic... more Background: Despite being one of the most studied families within the Carnivora, the phylogenetic relationships among the members of the bear family (Ursidae) have long remained unclear. Widely divergent topologies have been suggested based on various data sets and methods.

Journal of Visualized Experiments, 2009

We present a method of targeted DNA sequence retrieval from DNA sources which are heavily degrade... more We present a method of targeted DNA sequence retrieval from DNA sources which are heavily degraded and contaminated with microbial DNA, as is typical of ancient bones. The method greatly reduces sample destruction and sequencing demands relative to direct PCR or shotgun sequencing approaches. We used this method to reconstruct the complete mitochondrial DNA (mtDNA) genomes of five Neandertals from across their geographic range. The mtDNA genetic diversity of the late Neandertals was approximately three times lower than that of contemporary modern humans. Together with analyses of mtDNA protein evolution, these data suggest that the long-term effective population size of Neandertals was smaller than that of modern humans and extant great apes.

Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we... more Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing and analysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of sequence identities between Neanderthal and chimpanzee at sites where the human genomic sequence is different. These results enabled us to calculate the human-Neanderthal divergence time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor~706,000 years ago, and that the human and Neanderthal ancestral populations split~370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.

Molecular Biology and Evolution, 2009

Nucleic Acids Research, 2008

Current efforts to recover the Neandertal and mammoth genomes by 454 DNA sequencing demonstrate t... more Current efforts to recover the Neandertal and mammoth genomes by 454 DNA sequencing demonstrate the sensitivity of this technology. However, routine 454 sequencing applications still require microgram quantities of initial material. This is due to a lack of effective methods for quantifying 454 sequencing libraries, necessitating expensive and labour-intensive procedures when sequencing ancient DNA and other poor DNA samples. Here we report a 454 sequencing library quantification method based on quantitative PCR that effectively eliminates these limitations. We estimated both the molecule numbers and the fragment size distributions in sequencing libraries derived from Neandertal DNA extracts, SAGE ditags and bonobo genomic DNA, obtaining optimal sequencing yields without performing any titration runs. Using this method, 454 sequencing can routinely be performed from as little as 50 pg of initial material without titration runs, thereby drastically reducing costs while increasing the scope of sample throughput and protocol development on the 454 platform. The method should also apply to Illumina/Solexa and ABI/SOLiD sequencing, and should therefore help to widen the accessibility of all three platforms.

Current Biology, 2010

The recovery of DNA sequences from early modern humans (EMHs) could shed light on their interacti... more The recovery of DNA sequences from early modern humans (EMHs) could shed light on their interactions with archaic groups such as Neandertals and their relationships to current human populations. However, such experiments are highly problematic because present-day human DNA frequently contaminates bones . For example, in a recent study of mitochondrial (mt) DNA from Neolithic European skeletons, sequence variants were only taken as authentic if they were absent or rare in the present population, whereas others had to be discounted as possible contamination . This limits analysis to EMH individuals carrying rare sequences and thus yields a biased view of the ancient gene pool. Other approaches of identifying contaminating DNA, such as genotyping all individuals who have come into contact with a sample, restrict analyses to specimens where this is possible [5, 6] and do not exclude all possible sources of contamination. By studying mtDNA in Neandertal remains, where contamination and endogenous DNA can be distinguished by sequence, we show that fragmentation patterns and nucleotide misincorporations can be used to gauge authenticity of ancient DNA sequences. We use these features to determine a complete mtDNA sequence from a w30,000-year-old EMH from the Kostenki 14 site in Russia.

Genome Biology, 2005

Functional analysis of human and chimpanzee promoters

Twelve promoters of genes differentially... more Functional analysis of human and chimpanzee promoters

Twelve promoters of genes differentially expressed between humans and chimpanzees were tested for expression activity in culture cells. Seven promoters showed a significant difference in expression level between the human and chimpanzee promoter, but only three were in the same direction as the tissues, indicating that relevant expression differences between humans and chimpanzees will be difficult to predict from cell culture experiments or DNA sequences

Proceedings of The National Academy of Sciences, 2007

High-throughput direct sequencing techniques have recently opened the possibility to sequence gen... more High-throughput direct sequencing techniques have recently opened the possibility to sequence genomes from Pleistocene organisms. Here we analyze DNA sequences determined from a Neandertal, a mammoth, and a cave bear. We show that purines are overrepresented at positions adjacent to the breaks in the ancient DNA, suggesting that depurination has contributed to its degradation. We furthermore show that substitutions resulting from miscoding cytosine residues are vastly overrepresented in the DNA sequences and drastically clustered in the ends of the molecules, whereas other substitutions are rare. We present a model where the observed substitution patterns are used to estimate the rate of deamination of cytosine residues in single-and doublestranded portions of the DNA, the length of single-stranded ends, and the frequency of nicks. The results suggest that reliable genome sequences can be obtained from Pleistocene organisms.

Mitochondrial DNA sequences were identified amongst all sequence reads using the following criter... more Mitochondrial DNA sequences were identified amongst all sequence reads using the following criteria: First, each sequence was required to be >30 nucleotides long and show >90% identity to the reference human mtDNA sequence (GI:17981852) or against a version of this sequence where the HVRI had been substituted for the Vindija-80 HVRI when compared by megablast (-b10 -v 10 -U F -I T -e 0.001 -F F -a 1 -D 2 -W 16). Second, alignment bit scores were required to be at least as high as the best scoring alignment against the human nuclear genome. All such mtDNA fragment were then semi-globally aligned to the reference human mtDNA sequence and merged using the human mtDNA to order and orient each mtDNA fragment.

Nature, 2010

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequen... more Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4-6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population `Denisovans' and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.

Science, 2010

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Eu... more Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

BMC Evolutionary Biology, 2008

The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibilit... more The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibility to different pathogens. It has been estimated that all genetic variation underlying the human ABO alleles appeared along the human lineage, after the divergence from the chimpanzee lineage. A paleogenetic analysis of the ABO blood group gene in Neandertals allows us to directly test for the presence of the ABO alleles in these extinct humans.

Nature, 2011

Technological advances in DNA recovery and sequencing have drastically expanded the scope of gene... more Technological advances in DNA recovery and sequencing have drastically expanded the scope of genetic analyses of ancient specimens to the extent that full genomic investigations are now feasible and are quickly becoming standard. This trend has important implications for infectious disease research because genomic data from ancient microbes may help to elucidate mechanisms of pathogen evolution and adaptation for emerging and re-emerging infections. Here we report a reconstructed ancient genome of Yersinia pestis at 30-fold average coverage from Black Death victims securely dated to episodes of pestilence-associated mortality in London, England, 1348-1350. Genetic architecture and phylogenetic analysis indicate that the ancient organism is ancestral to most extant strains and sits very close to the ancestral node of all Y. pestis commonly associated with human infection. Temporal estimates suggest that the Black Death of 1347-1351 was the main historical event responsible for the introduction and widespread dissemination of the ancestor to all currently circulating Y. pestis strains pathogenic to humans, and further indicates that contemporary Y. pestis epidemics have their origins in the medieval era. Comparisons against modern genomes reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype. These findings support the notion that factors other than microbial genetics, such as environment, vector dynamics and host susceptibility, should be at the forefront of epidemiological discussions regarding emerging Y. pestis infections.

BMC Evolutionary Biology, 2008

Background: Despite being one of the most studied families within the Carnivora, the phylogenetic... more Background: Despite being one of the most studied families within the Carnivora, the phylogenetic relationships among the members of the bear family (Ursidae) have long remained unclear. Widely divergent topologies have been suggested based on various data sets and methods.

Journal of Visualized Experiments, 2009

We present a method of targeted DNA sequence retrieval from DNA sources which are heavily degrade... more We present a method of targeted DNA sequence retrieval from DNA sources which are heavily degraded and contaminated with microbial DNA, as is typical of ancient bones. The method greatly reduces sample destruction and sequencing demands relative to direct PCR or shotgun sequencing approaches. We used this method to reconstruct the complete mitochondrial DNA (mtDNA) genomes of five Neandertals from across their geographic range. The mtDNA genetic diversity of the late Neandertals was approximately three times lower than that of contemporary modern humans. Together with analyses of mtDNA protein evolution, these data suggest that the long-term effective population size of Neandertals was smaller than that of modern humans and extant great apes.

Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we... more Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing and analysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of sequence identities between Neanderthal and chimpanzee at sites where the human genomic sequence is different. These results enabled us to calculate the human-Neanderthal divergence time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor~706,000 years ago, and that the human and Neanderthal ancestral populations split~370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.

Molecular Biology and Evolution, 2009

Nucleic Acids Research, 2008

Current efforts to recover the Neandertal and mammoth genomes by 454 DNA sequencing demonstrate t... more Current efforts to recover the Neandertal and mammoth genomes by 454 DNA sequencing demonstrate the sensitivity of this technology. However, routine 454 sequencing applications still require microgram quantities of initial material. This is due to a lack of effective methods for quantifying 454 sequencing libraries, necessitating expensive and labour-intensive procedures when sequencing ancient DNA and other poor DNA samples. Here we report a 454 sequencing library quantification method based on quantitative PCR that effectively eliminates these limitations. We estimated both the molecule numbers and the fragment size distributions in sequencing libraries derived from Neandertal DNA extracts, SAGE ditags and bonobo genomic DNA, obtaining optimal sequencing yields without performing any titration runs. Using this method, 454 sequencing can routinely be performed from as little as 50 pg of initial material without titration runs, thereby drastically reducing costs while increasing the scope of sample throughput and protocol development on the 454 platform. The method should also apply to Illumina/Solexa and ABI/SOLiD sequencing, and should therefore help to widen the accessibility of all three platforms.

Current Biology, 2010

The recovery of DNA sequences from early modern humans (EMHs) could shed light on their interacti... more The recovery of DNA sequences from early modern humans (EMHs) could shed light on their interactions with archaic groups such as Neandertals and their relationships to current human populations. However, such experiments are highly problematic because present-day human DNA frequently contaminates bones . For example, in a recent study of mitochondrial (mt) DNA from Neolithic European skeletons, sequence variants were only taken as authentic if they were absent or rare in the present population, whereas others had to be discounted as possible contamination . This limits analysis to EMH individuals carrying rare sequences and thus yields a biased view of the ancient gene pool. Other approaches of identifying contaminating DNA, such as genotyping all individuals who have come into contact with a sample, restrict analyses to specimens where this is possible [5, 6] and do not exclude all possible sources of contamination. By studying mtDNA in Neandertal remains, where contamination and endogenous DNA can be distinguished by sequence, we show that fragmentation patterns and nucleotide misincorporations can be used to gauge authenticity of ancient DNA sequences. We use these features to determine a complete mtDNA sequence from a w30,000-year-old EMH from the Kostenki 14 site in Russia.

Genome Biology, 2005

Functional analysis of human and chimpanzee promoters

Twelve promoters of genes differentially... more Functional analysis of human and chimpanzee promoters

Twelve promoters of genes differentially expressed between humans and chimpanzees were tested for expression activity in culture cells. Seven promoters showed a significant difference in expression level between the human and chimpanzee promoter, but only three were in the same direction as the tissues, indicating that relevant expression differences between humans and chimpanzees will be difficult to predict from cell culture experiments or DNA sequences

Proceedings of The National Academy of Sciences, 2007

High-throughput direct sequencing techniques have recently opened the possibility to sequence gen... more High-throughput direct sequencing techniques have recently opened the possibility to sequence genomes from Pleistocene organisms. Here we analyze DNA sequences determined from a Neandertal, a mammoth, and a cave bear. We show that purines are overrepresented at positions adjacent to the breaks in the ancient DNA, suggesting that depurination has contributed to its degradation. We furthermore show that substitutions resulting from miscoding cytosine residues are vastly overrepresented in the DNA sequences and drastically clustered in the ends of the molecules, whereas other substitutions are rare. We present a model where the observed substitution patterns are used to estimate the rate of deamination of cytosine residues in single-and doublestranded portions of the DNA, the length of single-stranded ends, and the frequency of nicks. The results suggest that reliable genome sequences can be obtained from Pleistocene organisms.