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Tag: Genetics & Genomics

  • Rapid evolution predicted recovery after drought in scarlet monkeyflower

    What the study found

    The study found that population recovery after exceptional drought was predictable from standing genetic variation and rapid evolution at climate-associated loci in scarlet monkeyflower, a plant species also known as Mimulus cardinalis. It also found that genetic variation at adaptive loci, but not neutral loci, predicted recovery.

    Why the authors say this matters

    The authors conclude that the findings demonstrate the possibility of evolutionary rescue in the wild. The study suggests that rapid evolution may help some declining populations persist during climate change.

    What the researchers tested

    The researchers used whole-genome sequencing across 55 populations to identify climate-associated loci. They also tracked population size and allele frequency changes throughout the drought in order to link evolution with demographic change.

    What worked and what didn't

    They observed range-wide population decline during the drought. They also found geographically variable rapid evolution and variable population recovery, and the recovery pattern was associated with standing genetic variation and rapid evolution at climate-associated loci. In contrast, neutral loci did not predict population recovery.

    What to keep in mind

    The abstract does not describe detailed limitations beyond the study's focus on one species and one exceptional drought event. It also does not provide information about mechanisms beyond the reported associations.

    • Scarlet monkeyflower populations declined across their range during an exceptional drought.
    • Recovery after drought varied among populations.
    • Standing genetic variation and rapid evolution at climate-associated loci predicted recovery.
    • Genetic variation at neutral loci did not predict recovery.
    • The authors describe the findings as evidence for evolutionary rescue in the wild.

  • Extended wgsLR handles unknown genotyping error probabilities

    What the study found

    The study found that the wgsLR model can be extended to handle different genotyping error probabilities for trace and reference samples, including unknown error probabilities. The authors also report that an unknown genotyping error probability in the trace sample could be handled when there were enough independent markers.

    Why the authors say this matters

    The authors say this matters because shotgun DNA sequencing is becoming more relevant in forensic genetics for low-quality trace samples that cannot yield short tandem repeat profiles. They suggest that statistical models for interpreting this evidence need to account properly for sequencing errors.

    What the researchers tested

    The researchers extended the wgsLR model, which evaluates evidential strength by comparing genotypes in a trace sample and a reference sample under a single-source assumption. They added support for asymmetric genotyping error probabilities and for unknown error probabilities using both profile likelihood maximization and a prior distribution.

    What worked and what didn't

    The extensions were reported to work for unknown genotyping error probability in the trace sample when the analysis included a sufficient number of independent markers. The results were also reported to be robust to different prior distribution specifications, and the model was found robust against overdispersion.

    What to keep in mind

    The abstract does not describe detailed limitations beyond the need for a sufficient number of independent markers. It also does not provide numerical performance results or specify how broadly the findings apply beyond the cases discussed.

    • The wgsLR model was extended to allow asymmetric genotyping error probabilities.
    • The model was also extended to handle unknown error probabilities using profile likelihood and a prior distribution.
    • Unknown trace-sample genotyping error could be handled when enough independent markers were available.
    • Results were reported as robust to different prior distribution specifications.
    • The model was found robust against overdispersion.

  • Ancient DNA relatedness methods vary in reliability

    What the study found

    The study found that the reliability of ancient DNA relatedness estimation methods cannot be predicted from sample coverage alone. The authors report that method performance may be affected by multiple sources of bias.

    Why the authors say this matters

    The authors say this matters because these methods are often used to reconstruct genealogies in archaeological funerary contexts. They conclude that users need to consider method-specific strengths and limitations when interpreting results.

    What the researchers tested

    The researchers compared six ancient DNA relatedness estimation methods. They used a benchmark called BADGER, an automated pipeline that simulates pedigrees using randomly selected present-day individuals from the 1000 Genomes dataset and then generates raw ancient DNA sequence data for each person in the simulated family trees.

    What worked and what didn't

    The study examined performance across five factors: sample coverage, post-mortem damage correction methods, human contamination, genetic diversity, and inbreeding. The abstract says the benchmark allowed the authors to discuss individual strengths and limitations, but it does not provide a method-by-method ranking or detailed quantitative results in the available summary.

    What to keep in mind

    The abstract does not give the specific results for each of the six methods. It also does not describe the full range of limitations beyond noting that reliability may be influenced by several biases.

    • Six ancient DNA relatedness estimation methods were compared.
    • BADGER was created to simulate pedigrees and ancient DNA sequence data for benchmarking.
    • Performance was tested across sample coverage, damage correction, contamination, genetic diversity, and inbreeding.
    • Reliability could not be predicted from sample coverage alone.
    • The abstract says multiple sources of bias can affect method reliability.

  • Review highlights cell-cycle histone marks in C. elegans embryos

    What the study found

    The review says that several histone post-translational modifications are major epigenetic marks affected by the cell cycle during Caenorhabditis elegans embryogenesis. It specifically highlights H4K20me1, H3S10ph, H4S1ph, H2AS1ph, and H3T118ph.

    Why the authors say this matters

    The authors present these marks as important for understanding chromosome dynamics during the mitotic cell cycle. They say the review uses a comparative approach to emphasize histone modifications that are well documented in the C. elegans literature.

    What the researchers tested

    This is a comparative review rather than an experiment. The authors reviewed published work on histone post-translational modifications during embryogenesis in Caenorhabditis elegans, focusing on marks linked to the mitotic cell cycle.

    What worked and what didn't

    The review identifies five histone modifications as the main marks it focuses on: H4K20me1, H3S10ph, H4S1ph, H2AS1ph, and H3T118ph. The abstract does not report experimental outcomes, comparisons with control conditions, or negative results.

    What to keep in mind

    The available summary does not describe limitations, and the article is a review, so it does not present new experimental data in the abstract. Its scope is limited to histone modifications discussed in the context of mitotic cell cycles during C. elegans embryogenesis.

    • The article is a comparative review of histone modifications in C. elegans embryogenesis.
    • It highlights five post-translational histone marks: H4K20me1, H3S10ph, H4S1ph, H2AS1ph, and H3T118ph.
    • The authors frame these marks in relation to the mitotic cell cycle and chromosome dynamics.
    • The abstract describes the marks as well documented in the C. elegans literature.
    • No new experimental results or limitations are described in the abstract.

  • Ancient genomes show a population turnover in the Paris Basin

    What the study found

    The study found that the two burial phases at Bury in the Paris Basin were largely genetically discontinuous, meaning they belonged to different genetic groups. The authors link this difference to a northward movement of Neolithic ancestry from the south after the Neolithic decline.

    Why the authors say this matters

    The authors suggest these findings help explain the population turnover at the end of the fourth millennium BC and offer a possible explanation for the cessation of megalith building. The study also suggests that western Europe did not follow the same replacement pattern seen in Scandinavia, where farming communities were replaced by people with steppe ancestry.

    What the researchers tested

    The researchers sequenced 132 ancient genomes from the allée sépulcrale at Bury near Paris. They compared two burial phases separated by a period with no burial activity: one phase before the Neolithic decline and one after it. They also examined three large pedigrees, evidence of infectious diseases, and evidence for forest regrowth between the two phases.

    What worked and what didn't

    Their analysis showed that the two burial phases represented largely discontinuous genetic groups and different social organizations, as inferred from the pedigrees. The later phase appears to reflect Neolithic ancestry that spread into the Paris Basin after the decline, around 2900 BC. The dataset also contained genetic evidence of infectious diseases including Yersinia pestis and Borrelia recurrentis, alongside evidence for forest regrowth between the phases.

    What to keep in mind

    The abstract does not provide detailed limitations beyond the study being centered on one site, Bury, in the Paris area. It also does not state that the observed factors directly caused the population turnover or the end of megalith building.

    • Two burial phases at Bury were largely genetically discontinuous.
    • Neolithic ancestry from the south appears to have spread into the Paris Basin only after the Neolithic decline, around 2900 BC.
    • Three large pedigrees suggested different social organization in the two phases.
    • Genetic evidence of Yersinia pestis and Borrelia recurrentis was present in the dataset.
    • The abstract also notes evidence for forest regrowth between the two burial phases.

  • Newfoundland white blobs were identified as non-hazardous plant oil-based material

    What the study found

    The study found that the white blobs were most likely a plant oil-based material with polymeric components. The analysis also indicated that the substance was not petroleum-derived, not biodiesel, not silicone-based, and not chlorinated.

    Why the authors say this matters

    The authors state that the findings help explain the nature of the spill and show the value of multidisciplinary forensic approaches in environmental incident response. The study also notes that the incident raised public concerns about possible health, safety, and environmental impacts.

    What the researchers tested

    Researchers conducted a forensic analysis of the unidentified white blobs found at Ship Cove Beach in Newfoundland, Canada, in September 2024. They used physicochemical characterization, spectroscopy, mass spectrometry, and elemental analysis to determine the material's composition, nature, and possible origin.

    What worked and what didn't

    Chemical fingerprinting suggested that the sample was unlikely to be petroleum-derived or contaminated by petroleum products. It also suggested that biodiesel, silicone sealants, and chlorinated vinyl compounds were improbable, while aldehydes, fatty acids, and plant-derived sterols pointed toward a plant oil-based origin; high molecular weight compounds and thermal transformation behavior indicated polymeric materials, and the substance was described as neither flammable, combustible, corrosive, oxidizing, nor radioactive.

    What to keep in mind

    The abstract does not describe detailed limitations, so only the information above can be confirmed from the available summary. The origin is presented as an analytical interpretation based on the reported tests, not as a fully resolved source history.

    • White blobs were found on Ship Cove Beach, Newfoundland, in September 2024.
    • Forensic testing suggested a plant oil-based origin with polymeric materials.
    • The sample was unlikely to be petroleum-derived, biodiesel, silicone-based, or chlorinated.
    • The substance was described as neither flammable, combustible, corrosive, oxidizing, nor radioactive.
    • The authors say the work helps explain the spill and shows the value of multidisciplinary forensic analysis.

  • ZooMS identified ivory provenance in fragmented La Beleña remains

    What the study found

    The study found that traditional shape-based identification was often unreliable for the fragmented ivory and bone remains from La Beleña. Zooarchaeology by Mass Spectrometry (ZooMS), a protein-based identification method, identified all ivory samples as African elephant ivory and corrected several earlier misidentifications.

    Why the authors say this matters

    The authors conclude that current ivory identification and provenance protocols should be revised, and that open-access reference databases should be expanded. The study suggests that integrating biomolecular methods, especially proteomics, offers a more reliable way to trace prehistoric exchange networks and understand the cultural significance of ivory.

    What the researchers tested

    The researchers analyzed 119 osseous and ivory fragments from the necropolis of La Beleña in Córdoba, Spain, dating to the second half of the 4th to the beginning of the 3rd millennium BC. They combined macroscopic and microscopic observation with ZooMS, Fourier Transform Infrared Spectroscopy (FTIR), and ancient DNA (aDNA) extraction.

    What worked and what didn't

    Morphological criteria had significant limits in a highly fragmented assemblage. FTIR had limited ability to distinguish ivory from bone or one elephantid species from another, and aDNA produced too little endogenous material for analysis. ZooMS worked best in this study, identifying all ivory samples as African elephants and revealing that both transverse and longitudinal tusk exploitation were used; the objects were deposited as decorated finished items, consistent with funerary practices at other Iberian Chalcolithic sites.

    What to keep in mind

    The abstract describes challenges specific to fragmented prehistoric material, so the findings are limited to this kind of context. It also notes that aDNA was not useful here because of insufficient endogenous material, but it does not provide broader limits beyond the methods and sample set described.

    • Traditional morphological identification was unreliable for the fragmented La Beleña assemblage.
    • ZooMS identified all ivory samples as coming from African elephants (Loxodonta).
    • FTIR could not clearly separate ivory from bone or distinguish elephantid species well.
    • Ancient DNA extraction produced insufficient endogenous material for analysis.
    • The ivory objects were deposited as decorated finished items, and both transverse and longitudinal tusk exploitation were observed.