Publications by authors named "Valk T"

Article Synopsis
  • - The alignment of sequencing reads is crucial for studying ancient genomes, but challenges like reference bias and spurious mappings can lead to inaccurate results, especially as new lab techniques produce larger datasets.
  • - The study introduces AMBER, a new bioinformatics tool designed to evaluate ancient DNA mapping quality, providing insights into reference bias and mismatch rates across various read lengths.
  • - AMBER allows researchers to analyze factors affecting mapping accuracy, showing that the choice of mapping algorithms and quality thresholds significantly influences results, which can help improve alignment strategies for ancient DNA.
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A number of species have recently recovered from near-extinction. Although these species have avoided the immediate extinction threat, their long-term viability remains precarious due to the potential genetic consequences of population declines, which are poorly understood on a timescale beyond a few generations. Woolly mammoths (Mammuthus primigenius) became isolated on Wrangel Island around 10,000 years ago and persisted for over 200 generations before becoming extinct around 4,000 years ago.

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Article Synopsis
  • Genomic techniques can significantly enhance conservation efforts by identifying threats to various species and populations, as well as assisting in biodiversity restoration.
  • The text outlines two main areas of genomic research in conservation: vulnerability genomics, which focuses on assessing risks, and restoration genomics, which is aimed at recovery efforts.
  • Current applications of these genomic approaches are examined, along with key questions that remain unanswered and the future possibilities they hold for enhancing conservation strategies.
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Genome sequencing is a powerful tool to understand species evolutionary history, uncover genes under selection, which could be informative of local adaptation, and infer measures of genetic diversity, inbreeding and mutational load that could be used to inform conservation efforts. Gorillas, critically endangered primates, have received considerable attention and with the recently sequenced Bwindi mountain gorilla population, genomic data is now available from all gorilla subspecies and both mountain gorilla populations. Here, we reanalysed this rich dataset with a focus on evolutionary history, local adaptation and genomic parameters relevant for conservation.

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Article Synopsis
  • - Genomic studies on endangered species help us understand how they evolve and survive despite population declines and bottlenecks, offering clues on avoiding extinction.
  • - The researchers focused on the muskox, which nearly went extinct after the last Ice Age but is now thriving, examining 108 whole genomes from current populations and an ancient specimen.
  • - They found that past climate changes influenced muskox demographics, with the white-faced subspecies showing extremely low genetic variation without signs of inbreeding depression, suggesting that gradual population declines might have removed harmful mutations.
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Scots pine (Pinus sylvestris L.) is one of the most widespread and economically important conifer species in the world. Applications like genomic selection and association studies, which could help accelerate breeding cycles, are challenging in Scots pine because of its large and repetitive genome.

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Analysis of microbial data from archaeological samples is a growing field with great potential for understanding ancient environments, lifestyles, and diseases. However, high error rates have been a challenge in ancient metagenomics, and the availability of computational frameworks that meet the demands of the field is limited. Here, we propose aMeta, an accurate metagenomic profiling workflow for ancient DNA designed to minimize the amount of false discoveries and computer memory requirements.

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Typically much smaller in number than their mainland counterparts, island populations are ideal systems to investigate genetic threats to small populations. The Svalbard reindeer () is an endemic subspecies that colonized the Svalbard archipelago ca. 6,000-8,000 years ago and now shows numerous physiological and morphological adaptations to its arctic habitat.

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Archaic admixture has had a substantial impact on human evolution with multiple events across different clades, including from extinct hominins such as Neanderthals and Denisovans into modern humans. In great apes, archaic admixture has been identified in chimpanzees and bonobos but the possibility of such events has not been explored in other species. Here, we address this question using high-coverage whole-genome sequences from all four extant gorilla subspecies, including six newly sequenced eastern gorillas from previously unsampled geographic regions.

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Against the backdrop of a failing vaccine innovation system, innovation policy aimed at creating a COVID-19 vaccine was surprisingly fast and effective. This paper analyzes the influence of the COVID-19 landscape shock and corresponding innovation policy responses on the existing vaccine innovation system. We use document analysis and expert interviews, performed during vaccine development.

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Article Synopsis
  • Scientists studied 23 woolly mammoth genomes to learn how these creatures adapted over time, even looking at one that was 700,000 years old.
  • They found that the woolly mammoth already had many important genes for things like hair, fat storage, and its immune system when it first appeared.
  • The research shows that different genes helped the woolly mammoth change during its long existence, including some that affected its size and ear shape in later years.
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The aim of this study was to develop and validate an algorithm that can identify the type, frequency, and duration of activities common to intensive care (IC) patients. Ten healthy participants wore two accelerometers on their chest and leg while performing 14 activities clustered into four protocols (i.e.

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Background: Understanding the micro--evolutionary response of populations to demographic declines is a major goal in evolutionary and conservation biology. In small populations, genetic drift can lead to an accumulation of deleterious mutations, which will increase the risk of extinction. However, demographic recovery can still occur after extreme declines, suggesting that natural selection may purge deleterious mutations, even in extremely small populations.

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Woolly mammoths had a set of adaptations that enabled them to thrive in the Arctic environment. Many mammoth-specific single nucleotide polymorphisms (SNPs) responsible for unique mammoth traits have been previously identified from ancient genomes. However, a multitude of other genetic variants likely contributed to woolly mammoth evolution.

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Background: Many wild species have suffered drastic population size declines over the past centuries, which have led to 'genomic erosion' processes characterized by reduced genetic diversity, increased inbreeding, and accumulation of harmful mutations. Yet, genomic erosion estimates of modern-day populations often lack concordance with dwindling population sizes and conservation status of threatened species. One way to directly quantify the genomic consequences of population declines is to compare genome-wide data from pre-decline museum samples and modern samples.

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Increasing habitat fragmentation leads to wild populations becoming small, isolated, and threatened by inbreeding depression. However, small populations may be able to purge recessive deleterious alleles as they become expressed in homozygotes, thus reducing inbreeding depression and increasing population viability. We used whole-genome sequences from 57 tigers to estimate individual inbreeding and mutation load in a small-isolated and two large-connected populations in India.

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Background: Clinical trials often suffer from recruitment barriers and poor adherence, which increases costs and affects trial outcomes.

Objective: To investigate the feasibility of Decentralized Clinical Trial (DCT) design elements to recruit, enroll, and engage patients with type 2 diabetes mellitus (T2DM).

Methods: Patients with T2DM were recruited through a pharmacy and online recruitment using advert on Facebook, to 3 weeks monitoring of glucose and behaviometric parameters.

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The kākāpō is a flightless parrot endemic to New Zealand. Once common in the archipelago, only 201 individuals remain today, most of them descending from an isolated island population. We report the first genome-wide analyses of the species, including a high-quality genome assembly for kākāpō, one of the first chromosome-level reference genomes sequenced by the Vertebrate Genomes Project (VGP).

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Only five species of the once-diverse Rhinocerotidae remain, making the reconstruction of their evolutionary history a challenge to biologists since Darwin. We sequenced genomes from five rhinoceros species (three extinct and two living), which we compared to existing data from the remaining three living species and a range of outgroups. We identify an early divergence between extant African and Eurasian lineages, resolving a key debate regarding the phylogeny of extant rhinoceroses.

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Complications of Coronavirus Disease 2019 (COVID-19) occur with increased frequency in people admitted to the hospital with diabetes or hyperglycemia. The increased risk for COVID-19 infections in the presence of these metabolic conditions is in part due to overlapping pathophysiologic features of COVID-19, diabetes, and glucose control. Various antiviral treatments are being tested in COVID-19 patients.

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Article Synopsis
  • Small populations, like the Sumatran rhinoceros, face threats from inbreeding and mutational load, increasing their extinction risk.
  • Analysis of genomes from historical and current populations reveals that the Malay Peninsula population underwent increased inbreeding before likely extinction, while Sumatra and Borneo populations show low inbreeding but high mutational load.
  • The findings suggest future challenges from inbreeding depression in these small populations but indicate that assisted gene flow might help improve genetic diversity and resilience.
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Temporal genomic data hold great potential for studying evolutionary processes such as speciation. However, sampling across speciation events would, in many cases, require genomic time series that stretch well back into the Early Pleistocene subepoch. Although theoretical models suggest that DNA should survive on this timescale, the oldest genomic data recovered so far are from a horse specimen dated to 780-560 thousand years ago.

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