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1.
Int J Mol Sci ; 25(7)2024 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-38612593

RESUMEN

The genetic contributions of Neanderthals to the modern human genome have been evidenced by the comparison of present-day human genomes with paleogenomes. Neanderthal signatures in extant human genomes are attributed to intercrosses between Neanderthals and archaic anatomically modern humans (AMHs). Although Neanderthal signatures are well documented in the nuclear genome, it has been proposed that there is no contribution of Neanderthal mitochondrial DNA to contemporary human genomes. Here we show that modern human mitochondrial genomes contain 66 potential Neanderthal signatures, or Neanderthal single nucleotide variants (N-SNVs), of which 36 lie in coding regions and 7 result in nonsynonymous changes. Seven N-SNVs are associated with traits such as cycling vomiting syndrome, Alzheimer's disease and Parkinson's disease, and two N-SNVs are associated with intelligence quotient. Based on recombination tests, principal component analysis (PCA) and the complete absence of these N-SNVs in 41 archaic AMH mitogenomes, we conclude that convergent evolution, and not recombination, explains the presence of N-SNVs in present-day human mitogenomes.


Asunto(s)
Enfermedad de Alzheimer , Genoma Mitocondrial , Hombre de Neandertal , Humanos , Animales , Hombre de Neandertal/genética , Mutación , Nucleótidos
2.
R Soc Open Sci ; 11(4): 231835, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38601034

RESUMEN

The southern Mendoza province, located in the northern region of Patagonia, was inhabited by hunter-gatherer groups until historic times. Previous archaeological studies have reported canid remains among faunal assemblages, which were assumed to be part of the human diet. However, the taxonomic identification and significance of these canids within human groups have raised questions. In this study, we used ancient DNA analysis, morphological examination and stable isotope analysis (δ13Ccol and δ15N) to re-evaluate the taxonomic assignment of a canid discovered at the Late Holocene burial site of Cañada Seca. Previous morphological identifications suggested that it belonged to the genus Lycalopex, but our results conclusively demonstrate that the individual belongs to the extinct fox species Dusicyon avus. This finding expands Dusicyon avus' known geographical distribution to Patagonia's northern extremity. Furthermore, statistical predictions based on genetic divergence undermine the hypothesis that hybridization between Canis and Dusicyon, facilitated by the introduction of domestic dogs, played a role in the extinction of Dusicyon species. On the other hand, our findings indicate that a Dusicyon avus individual shared a similar diet and was probably buried alongside humans, suggesting a close relationship between the two species during their lives and deaths.

3.
Philos Trans R Soc Lond B Biol Sci ; 379(1902): 20230017, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38583481

RESUMEN

Ecosystem response to climate change is complex. In order to forecast ecosystem dynamics, we need high-quality data on changes in past species abundance that can inform process-based models. Sedimentary ancient DNA (sedaDNA) has revolutionised our ability to document past ecosystems' dynamics. It provides time series of increased taxonomic resolution compared to microfossils (pollen, spores), and can often give species-level information, especially for past vascular plant and mammal abundances. Time series are much richer in information than contemporary spatial distribution information, which have been traditionally used to train models for predicting biodiversity and ecosystem responses to climate change. Here, we outline the potential contribution of sedaDNA to forecast ecosystem changes. We showcase how species-level time series may allow quantification of the effect of biotic interactions in ecosystem dynamics, and be used to estimate dispersal rates when a dense network of sites is available. By combining palaeo-time series, process-based models, and inverse modelling, we can recover the biotic and abiotic processes underlying ecosystem dynamics, which are traditionally very challenging to characterise. Dynamic models informed by sedaDNA can further be used to extrapolate beyond current dynamics and provide robust forecasts of ecosystem responses to future climate change. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.


Asunto(s)
ADN Antiguo , Ecosistema , Animales , Cambio Climático , Biodiversidad , Polen , Mamíferos
4.
Mitochondrion ; 76: 101871, 2024 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-38462159

RESUMEN

The ancient township of Vadnagar tells a story of a long chain of cultural diversity and exchange. Vadnagar has been continuously habituated and shows a presence of rich cultural amalgamation and continuous momentary sequences between the 2th century BCE and present-day. Seven cultural periods developed a complex and enriched settlement at Vadnagar in spatio-temporality. Although archaeological studies done on this oldest settlement suggested a rich cultural heritage, the genetic studies to pinpoint the genetic ancestry was lacking till date. In our current study we have for the first time reconstructed the complete mitogenomes of medieval individuals of the Vadnagar archaeological site in Gujarat. The study aimed to investigate the cosmopolitan nature of the present population as well as the migratory pattern and the inflow of different groups through trade, cultural and religious practices. Our analysis suggests heterogeneous nature of the medieval population of Vadnagar with presence of deeply rooted local ancestral components as well as central Asian genetic ancestry. This Central Asian component associated with mitochondrial haplotype U2e was not shared with any individual from India, but rather with individuals from the Bronze Age of Tajikistan and with an earlier age of coalescence. In summary, we propose that the medieval site of Vadnagar in western India was rich in cultural and genetic aspects, with both local and western Eurasian components.

5.
Biotechniques ; 76(5): 216-223, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38530148

RESUMEN

Ancient DNA (aDNA) obtained from human remains is typically fragmented and present in relatively low amounts. Here we investigate a set of optimal methods for producing aDNA data by comparing silica-based DNA extraction and aDNA library preparation protocols. We also test the efficiency of whole-genome enrichment (WGC) on ancient human samples by modifying a number of parameter combinations. We find that the Dabney extraction protocol performs significantly better than alternatives. We further observed a positive trend with the BEST library protocol indicating lower clonality. Notably, our results suggest that WGC is effective at retrieving endogenous DNA, particularly from poorly-preserved human samples, by increasing human endogenous proportions by 5x. Thus, aDNA studies will be most likely to benefit from our results.


Asunto(s)
ADN Antiguo , Genoma Humano , ADN Antiguo/análisis , ADN Antiguo/aislamiento & purificación , Humanos , Genoma Humano/genética , Biblioteca de Genes , Análisis de Secuencia de ADN/métodos , Dióxido de Silicio/química
6.
Mol Biol Evol ; 41(4)2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38507661

RESUMEN

Recent studies have suggested that dogs were domesticated during the Last Glacial Maximum (LGM) in Siberia, which contrasts with previous proposed domestication centers (e.g. Europe, the Middle East, and East Asia). Ancient DNA provides a powerful resource for the study of mammalian evolution and has been widely used to understand the genetic history of domestic animals. To understand the maternal genetic history of East Asian dogs, we have made a complete mitogenome dataset of 120 East Asian canids from 38 archaeological sites, including 102 newly sequenced from 12.9 to 1 ka BP (1,000 years before present). The majority (112/119, 94.12%) belonged to haplogroup A, and half of these (55/112, 49.11%) belonged to sub-haplogroup A1b. Most existing mitochondrial haplogroups were present in ancient East Asian dogs. However, mitochondrial lineages in ancient northern dogs (northeastern Eurasia and northern East Asia) were deeper and older than those in southern East Asian dogs. Results suggests that East Asian dogs originated from northeastern Eurasian populations after the LGM, dispersing in two possible directions after domestication. Western Eurasian (Europe and the Middle East) dog maternal ancestries genetically influenced East Asian dogs from approximately 4 ka BP, dramatically increasing after 3 ka BP, and afterwards largely replaced most primary maternal lineages in northern East Asia. Additionally, at least three major mitogenome sub-haplogroups of haplogroup A (A1a, A1b, and A3) reveal at least two major dispersal waves onto the Qinghai-Tibet Plateau in ancient times, indicating eastern (A1b and A3) and western (A1a) Eurasian origins.


Asunto(s)
Pueblos del Este de Asia , Genoma Mitocondrial , Humanos , Animales , Perros , ADN Mitocondrial/genética , Asia Oriental , Animales Domésticos/genética , Haplotipos , Variación Genética , Filogenia , Mamíferos/genética
7.
Curr Biol ; 34(7): 1587-1595.e5, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38552628

RESUMEN

Emperor Wu (, Wudi) of the Xianbei-led Northern Zhou dynasty, named Yuwen Yong (, 543-578 CE), was a highly influential emperor who reformed the system of regional troops, pacified the Turks, and unified the northern part of the country. His genetic profile and physical characteristics, including his appearance and potential diseases, have garnered significant interest from the academic community and the public. In this study, we have successfully generated a 0.343×-coverage genome of Wudi with 1,011,419 single-nucleotide polymorphisms (SNPs) on the 1240k panel. By analyzing pigmentation-relevant SNPs and conducting cranial CT-based facial reconstruction, we have determined that Wudi possessed a typical East or Northeast Asian appearance. Furthermore, pathogenic SNPs suggest Wudi faced an increased susceptibility to certain diseases, such as stroke. Wudi shared the closest genetic relationship with ancient Khitan and Heishui Mohe samples and modern Daur and Mongolian populations but also showed additional affinity with Yellow River (YR) farmers. We estimated that Wudi derived 61% of his ancestry from ancient Northeast Asians (ANAs) and nearly one-third from YR farmer-related groups. This can likely be attributed to continuous intermarriage between Xianbei royal families, and local Han aristocrats.1,2 Furthermore, our study has revealed genetic diversities among available ancient Xianbei individuals from different regions, suggesting that the formation of the Xianbei was a dynamic process influenced by admixture with surrounding populations.


Asunto(s)
Pueblo Asiatico , ADN Mitocondrial , Humanos , ADN Mitocondrial/genética , Pueblo Asiatico/genética , Genoma , Polimorfismo de Nucleótido Simple , China , Genética de Población
8.
Mol Biol Evol ; 41(3)2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38466119

RESUMEN

Ancient DNA can directly reveal the contribution of natural selection to human genomic variation. However, while the analysis of ancient DNA has been successful at identifying genomic signals of selection, inferring the phenotypic consequences of that selection has been more difficult. Most trait-associated variants are noncoding, so we expect that a large proportion of the phenotypic effects of selection will also act through noncoding variation. Since we cannot measure gene expression directly in ancient individuals, we used an approach (Joint-Tissue Imputation [JTI]) developed to predict gene expression from genotype data. We tested for changes in the predicted expression of 17,384 protein coding genes over a time transect of 4,500 years using 91 present-day and 616 ancient individuals from Britain. We identified 28 genes at seven genomic loci with significant (false discovery rate [FDR] < 0.05) changes in predicted expression levels in this time period. We compared the results from our transcriptome-wide scan to a genome-wide scan based on estimating per-single nucleotide polymorphism (SNP) selection coefficients from time series data. At five previously identified loci, our approach allowed us to highlight small numbers of genes with evidence for significant shifts in expression from peaks that in some cases span tens of genes. At two novel loci (SLC44A5 and NUP85), we identify selection on gene expression not captured by scans based on genomic signatures of selection. Finally, we show how classical selection statistics (iHS and SDS) can be combined with JTI models to incorporate functional information into scans that use present-day data alone. These results demonstrate the potential of this type of information to explore both the causes and consequences of natural selection.


Asunto(s)
ADN Antiguo , Selección Genética , Humanos , Reino Unido , Genoma , Genotipo , Polimorfismo de Nucleótido Simple , Estudio de Asociación del Genoma Completo
9.
PeerJ ; 12: e16770, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38440408

RESUMEN

The taxonomic characterization of ancient microbiomes is a key step in the rapidly growing field of paleomicrobiology. While PCR amplification of the 16S ribosomal RNA (rRNA) gene is a widely used technique in modern microbiota studies, this method has systematic biases when applied to ancient microbial DNA. Shotgun metagenomic sequencing has proven to be the most effective method in reconstructing taxonomic profiles of ancient dental calculus samples. Nevertheless, shotgun sequencing approaches come with inherent limitations that could be addressed through hybridization enrichment capture. When employed together, shotgun sequencing and hybridization capture have the potential to enhance the characterization of ancient microbial communities. Here, we develop, test, and apply a hybridization enrichment capture technique to selectively target 16S rRNA gene fragments from the libraries of ancient dental calculus samples generated with shotgun techniques. We simulated data sets generated from hybridization enrichment capture, indicating that taxonomic identification of fragmented and damaged 16S rRNA gene sequences was feasible. Applying this enrichment approach to 15 previously published ancient calculus samples, we observed a 334-fold increase of ancient 16S rRNA gene fragments in the enriched samples when compared to unenriched libraries. Our results suggest that 16S hybridization capture is less prone to the effects of background contamination than 16S rRNA amplification, yielding a higher percentage of on-target recovery. While our enrichment technique detected low abundant and rare taxa within a given sample, these assignments may not achieve the same level of specificity as those achieved by unenriched methods.


Asunto(s)
Benchmarking , Microbiota , Humanos , ARN Ribosómico 16S/genética , Genes de ARNr , Cálculos Dentales , ADN Antiguo
10.
Am J Biol Anthropol ; 183(4): e24911, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38348756

RESUMEN

OBJECTIVES: This paper starts from the unusual observation of the overrepresentation of females among adults in the cemetery of Bronze Age Shahr-i Sokhta (Seistan, Iran) and explores the post marital residence pattern. By integrating taphonomical (skeletal preservation), anthropological (sex ratio [SR], sexual dimorphism, stress indicators, age at death), archeological (long distance trade indicators, habitation floor area, social role of women), and ancient DNA (heterozygosity levels in X chromosomes) data we test the hypothesis of post marital matrilocality in the site. METHODS: We computed the SR (pelvis-based sex determination) in a random unpublished adult sample from the cemetery of Shahr-i Sokhta and in two samples previously published by other authors. We used comparative data on SR from: a large Supra Regional multi-chronological sample of sites, n = 47, with 8808 adult sexed individuals, from Southern Europe, Egypt, Middle East, Southern Russia; a Regional Bronze Age sample of sites (n = 10) from Bactria Margiana and Indus Valley with 1324 adult sexed individuals. We estimated the heterozygosity levels in X chromosomes compared with the rest of the autosomes on the assumption that in a matrilocal society females should show lower variability than men. RESULTS: Adult SR in a sample (n = 549) from Shahr-i Sokhta is 70.5, the overrepresentation of females is shared with Regional Bronze Age sites from Bactria Margiana (SR = 72.09) and Indus Valley (SR = 67.54). On the contrary, in a larger Supra Regional multi-chronological sample of sites, mean SR ranges between 112.7 (Bronze Age) and 163.1 (Middle Ages). Taphonomical and anthropological indicators do not explain the overrepresentation of female skeletons. Archeological indicators suggest a high social status of women and that the society was devoted to long range trade activities. heterozygosity levels in X chromosomes are in agreement with a matrilocal society. CONCLUSIONS: Indicators suggest that Bronze Age Shahr-ì Sokhta was a matrilocal society and that long distance trade was an important economic factor producing an overrepresentation of adult female skeletons in the cemetery.


Asunto(s)
Cementerios , Polygonaceae , Adulto , Masculino , Persona de Mediana Edad , Humanos , Femenino , Irán , Razón de Masculinidad , Medio Oriente , Antropología
11.
Proc Natl Acad Sci U S A ; 121(9): e2312377121, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38363870

RESUMEN

Genomic time series from experimental evolution studies and ancient DNA datasets offer us a chance to directly observe the interplay of various evolutionary forces. We show how the genome-wide variance in allele frequency change between two time points can be decomposed into the contributions of gene flow, genetic drift, and linked selection. In closed populations, the contribution of linked selection is identifiable because it creates covariances between time intervals, and genetic drift does not. However, repeated gene flow between populations can also produce directionality in allele frequency change, creating covariances. We show how to accurately separate the fraction of variance in allele frequency change due to admixture and linked selection in a population receiving gene flow. We use two human ancient DNA datasets, spanning around 5,000 y, as time transects to quantify the contributions to the genome-wide variance in allele frequency change. We find that a large fraction of genome-wide change is due to gene flow. In both cases, after correcting for known major gene flow events, we do not observe a signal of genome-wide linked selection. Thus despite the known role of selection in shaping long-term polymorphism levels, and an increasing number of examples of strong selection on single loci and polygenic scores from ancient DNA, it appears to be gene flow and drift, and not selection, that are the main determinants of recent genome-wide allele frequency change. Our approach should be applicable to the growing number of contemporary and ancient temporal population genomics datasets.


Asunto(s)
Flujo Génico , Selección Genética , Humanos , ADN Antiguo , Frecuencia de los Genes , Flujo Genético , Genética de Población
12.
Curr Biol ; 34(5): 1142-1147.e6, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38350445

RESUMEN

Directly observing the chronology and tempo of adaptation in response to ecological change is rarely possible in natural ecosystems. Sedimentary ancient DNA (sedaDNA) has been shown to be a tractable source of genome-scale data of long-dead organisms1,2,3 and to thereby potentially provide an understanding of the evolutionary histories of past populations.4,5 To date, time series of ecosystem biodiversity have been reconstructed from sedaDNA, typically using DNA metabarcoding or shotgun sequence data generated from less than 1 g of sediment.6,7 Here, we maximize sequence coverage by extracting DNA from ∼50× more sediment per sample than the majority of previous studies1,2,3 to achieve genotype resolution. From a time series of Late Pleistocene sediments spanning from a marine to freshwater ecosystem, we compare adaptive genotypes reconstructed from the environmental genomes of three-spined stickleback at key time points of this transition. We find a staggered temporal dynamic in which freshwater alleles at known loci of large effect in marine-freshwater divergence of three-spined stickleback (e.g., EDA)8 were already established during the brackish phase of the formation of the isolation basin. However, marine alleles were still detected across the majority of marine-freshwater divergence-associated loci, even after the complete isolation of the lake from marine ingression. Our retrospective approach to studying adaptation from environmental genomes of three-spined sticklebacks at the end of the last glacial period complements contemporary experimental approaches9,10,11 and highlights the untapped potential for retrospective "evolve and resequence" natural experiments using sedaDNA.


Asunto(s)
Ecosistema , Smegmamorpha , Animales , Adaptación Fisiológica/genética , Smegmamorpha/genética , Estudios Retrospectivos , Lagos
13.
Am J Biol Anthropol ; : e24903, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-38308451

RESUMEN

OBJECTIVES: Determine the geographic place of origin and maternal lineage of prehistoric human skeletal remains discovered in Puyil Cave, Tabasco State, Mexico, located in a region currently populated by Olmec, Zoque and Maya populations. MATERIALS AND METHODS: All specimens were radiocarbon (14 C) dated (beta analytic), had dental modifications classified, and had an analysis of 13 homologous reference points conducted to evaluate artificial cranial deformation (ACD). Following DNA purification, hypervariable region I (HVR-1) of the mitogenome was amplified and Sanger sequenced. Finally, Next Generation Sequencing (NGS) was performed for total DNA. Mitochondrial DNA (mtDNA) variants and haplogroups were determined using BioEdit 7.2 and IGV software and confirmed with MITOMASTER and WebHome softwares. RESULTS: Radiocarbon dating (14 C) demonstrated that the inhabitants of Puyil Cave lived during the Archaic and Classic Periods and displayed tabular oblique and tabular mimetic ACD. These pre-Hispanic remains exhibited five mtDNA lineages: A, A2, C1, C1c and D4. Network analysis revealed a close genetic affinity between pre-Hispanic Puyil Cave inhabitants and contemporary Maya subpopulations from Mexico and Guatemala, as well as individuals from Bolivia, Brazil, the Dominican Republic, and China. CONCLUSIONS: Our results elucidate the dispersal of pre-Hispanic Olmec and Maya ancestors and suggest that ACD practices are closely related to Olmec and Maya practices. Additionally, we conclude that ACD has likely been practiced in the region since the Middle-Archaic Period.

14.
Genome Biol Evol ; 16(3)2024 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-38412309

RESUMEN

Microsatellites are widely used in population genetics, but their evolutionary dynamics remain poorly understood. It is unclear whether microsatellite loci drift in length over time. This is important because the mutation processes that underlie these important genetic markers are central to the evolutionary models that employ microsatellites. We identify more than 27 million microsatellites using a novel and unique dataset of modern and ancient Adélie penguin genomes along with data from 63 published chordate genomes. We investigate microsatellite evolutionary dynamics over 2 timescales: one based on Adélie penguin samples dating to ∼46.5 ka and the other dating to the diversification of chordates aged more than 500 Ma. We show that the process of microsatellite allele length evolution is at dynamic equilibrium; while there is length polymorphism among individuals, the length distribution for a given locus remains stable. Many microsatellites persist over very long timescales, particularly in exons and regulatory sequences. These often retain length variability, suggesting that they may play a role in maintaining phenotypic variation within populations.


Asunto(s)
Genética de Población , Genoma , Humanos , Mutación , Repeticiones de Microsatélite , Polimorfismo Genético
15.
Cell Genom ; 4(3): 100507, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38417441

RESUMEN

The harsh climate of Arabia has posed challenges in generating ancient DNA from the region, hindering the direct examination of ancient genomes for understanding the demographic processes that shaped Arabian populations. In this study, we report whole-genome sequence data obtained from four Tylos-period individuals from Bahrain. Their genetic ancestry can be modeled as a mixture of sources from ancient Anatolia, Levant, and Iran/Caucasus, with variation between individuals suggesting population heterogeneity in Bahrain before the onset of Islam. We identify the G6PD Mediterranean mutation associated with malaria resistance in three out of four ancient Bahraini samples and estimate that it rose in frequency in Eastern Arabia from 5 to 6 kya onward, around the time agriculture appeared in the region. Our study characterizes the genetic composition of ancient Arabians, shedding light on the population history of Bahrain and demonstrating the feasibility of studies of ancient DNA in the region.


Asunto(s)
Árabes , ADN Antiguo , Genética de Población , Genoma Humano , Humanos , Árabes/genética , Bahrein
16.
Trends Genet ; 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38423916

RESUMEN

Abundant and plentiful fruit crops are threatened by the loss of diverse legacy cultivars which are being replaced by a limited set of high-yielding ones. This article delves into the potential of paleogenomics that utilizes ancient DNA analysis to revive lost diversity. By focusing on grapevines, date palms, and tomatoes, recent studies showcase the effectiveness of paleogenomic techniques in identifying and understanding genetic traits crucial for crop resilience, disease resistance, and nutritional value. The approach not only tracks landrace dispersal and introgression but also sheds light on domestication events. In the face of major future environmental challenges, integrating paleogenomics with modern breeding strategies emerges as a promising avenue to significantly bolster fruit crop sustainability.

17.
J Forensic Sci ; 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38415845

RESUMEN

Genetic assessment of highly incinerated and/or degraded human skeletal material is a persistent challenge in forensic DNA analysis, including identifying victims of mass disasters. Few studies have investigated the impact of thermal degradation on whole-genome single-nucleotide polymorphism (SNP) quality and quantity using next-generation sequencing (NGS). We present whole-genome SNP data obtained from the bones and teeth of 27 fire victims using two DNA extraction techniques. Extracts were converted to double-stranded DNA libraries then enriched for whole-genome SNPs using unpublished biotinylated RNA baits and sequenced on an Illumina NextSeq 550 platform. Raw reads were processed using the EAGER (Efficient Ancient Genome Reconstruction) pipeline, and the SNPs filtered and called using FreeBayes and GATK (v. 3.8). Mixed-effects modeling of the data suggest that SNP variability and preservation is predominantly determined by skeletal element and burn category, and not by extraction type. Whole-genome SNP data suggest that selecting long bones, hand and foot bones, and teeth subjected to temperatures <350°C are the most likely sources for higher genomic DNA yields. Furthermore, we observed an inverse correlation between the number of captured SNPs and the extent to which samples were burned, as well as a significant decrease in the total number of SNPs measured for samples subjected to temperatures >350°C. Our data complement previous analyses of burned human remains that compare extraction methods for downstream forensic applications and support the idea of adopting a modified Dabney extraction technique when traditional forensic methods fail to produce DNA yields sufficient for genetic identification.

18.
ISME J ; 18(1)2024 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-38365253

RESUMEN

Current global warming results in rising sea-water temperatures, and the loss of sea ice in Arctic and subarctic oceans impacts the community composition of primary producers with cascading effects on the food web and potentially on carbon export rates. This study analyzes metagenomic shotgun and diatom rbcL amplicon sequencing data from sedimentary ancient DNA of the subarctic western Bering Sea that records phyto- and zooplankton community changes over the last glacial-interglacial cycles, including the last interglacial period (Eemian). Our data show that interglacial and glacial plankton communities differ, with distinct Eemian and Holocene plankton communities. The generally warm Holocene period is dominated by picosized cyanobacteria and bacteria-feeding heterotrophic protists, while the Eemian period is dominated by eukaryotic picosized chlorophytes and Triparmaceae. By contrast, the glacial period is characterized by microsized phototrophic protists, including sea ice-associated diatoms in the family Bacillariaceae and co-occurring diatom-feeding crustaceous zooplankton. Our deep-time record of plankton community changes reveals a long-term decrease in phytoplankton cell size coeval with increasing temperatures, resembling community changes in the currently warming Bering Sea. The phytoplankton community in the warmer-than-present Eemian period is distinct from modern communities and limits the use of the Eemian as an analog for future climate scenarios. However, under enhanced future warming, the expected shift toward the dominance of small-sized phytoplankton and heterotrophic protists might result in an increased productivity, whereas the community's potential of carbon export will be decreased, thereby weakening the subarctic Bering Sea's function as an effective carbon sink.


Asunto(s)
Cianobacterias , Diatomeas , Plancton/genética , ADN Antiguo , Océanos y Mares , Fitoplancton/genética , Diatomeas/genética , Cianobacterias/genética , Carbono , Ecosistema
19.
Mol Ecol Resour ; 24(3): e13913, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38173222

RESUMEN

The identification of sex-linked scaffolds and the genetic sex of individuals, i.e. their sex karyotype, is a fundamental step in population genomic studies. If sex-linked scaffolds are known, single individuals may be sexed based on read counts of next-generation sequencing data. If both sex-linked scaffolds as well as sex karyotypes are unknown, as is often the case for non-model organisms, they have to be jointly inferred. For both cases, current methods rely on arbitrary thresholds, which limits their power for low-depth data. In addition, most current methods are limited to euploid sex karyotypes (XX and XY). Here we develop BeXY, a fully Bayesian method to jointly infer the posterior probabilities for each scaffold to be autosomal, X- or Y-linked and for each individual to be any of the sex karyotypes XX, XY, X0, XXX, XXY, XYY and XXYY. If the sex-linked scaffolds are known, it also identifies autosomal trisomies and estimates the sex karyotype posterior probabilities for single individuals. As we show with downsampling experiments, BeXY has higher power than all existing methods. It accurately infers the sex karyotype of ancient human samples with as few as 20,000 reads and accurately infers sex-linked scaffolds from data sets of just a handful of samples or with highly imbalanced sex ratios, also in the case of low-quality reference assemblies. We illustrate the power of BeXY by applying it to both whole-genome shotgun and target enrichment sequencing data of ancient and modern humans, as well as several non-model organisms.


Asunto(s)
Genómica , Cromosomas Sexuales , Humanos , Teorema de Bayes , Cromosomas Sexuales/genética , Pruebas Genéticas , Cariotipo
20.
Mol Ecol Resour ; 24(3): e13926, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38189170

RESUMEN

Sedimentary ancient DNA (sedaDNA) has rarely been used to obtain population-level data due to either a lack of taxonomic resolution for the molecular method used, limitations in the reference material or inefficient methods. Here, we present the potential of multiplexing different PCR primers to retrieve population-level genetic data from sedaDNA samples. Vaccinium uliginosum (Ericaceae) is a widespread species with a circumpolar distribution and three lineages in present-day populations. We searched 18 plastid genomes for intraspecific variable regions and developed 61 primer sets to target these. Initial multiplex PCR testing resulted in a final set of 38 primer sets. These primer sets were used to analyse 20 lake sedaDNA samples (11,200 cal. yr BP to present) from five different localities in northern Norway, the Alps and the Polar Urals. All known V. uliginosum lineages in these regions and all primer sets could be recovered from the sedaDNA data. For each sample on average 28.1 primer sets, representing 34.15 sequence variants, were recovered. All sediment samples were dominated by a single lineage, except three Alpine samples which had co-occurrence of two different lineages. Furthermore, lineage turnover was observed in the Alps and northern Norway, suggesting that present-day phylogeographical studies may overlook past genetic patterns. Multiplexing primer is a promising tool for generating population-level genetic information from sedaDNA. The relatively simple method, combined with high sensitivity, provides a scalable method which will allow researchers to track populations through time and space using environmental DNA.


Asunto(s)
ADN Ambiental , Genética de Población , Filogeografía , ADN Antiguo/análisis , Reacción en Cadena de la Polimerasa Multiplex , Variación Genética
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