| 1. |
- Allentoft, Morten E., et al.
(author)
-
Population genomics of post-glacial western Eurasia
- 2024
-
In: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
-
Journal article (peer-reviewed)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
|
|
| 2. |
- Egfjord, Anne Friis Holm, et al.
(author)
-
Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark
- 2021
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16
-
Journal article (peer-reviewed)abstract
- The Gjerrild burial provides the largest and best-preserved assemblage of human skeletal material presently known from the Single Grave Culture (SGC) in Denmark. For generations it has been debated among archaeologists if the appearance of this archaeological complex represents a continuation of the previous Neolithic communities, or was facilitated by incoming migrants. We sampled and analysed five skeletons from the Gjerrild cist, buried over a period of c. 300 years, 2600/2500–2200 cal BCE. Despite poor DNA preservation, we managed to sequence the genome (>1X) of one individual and the partial genomes (0.007X and 0.02X) of another two individuals. Our genetic data document a female (Gjerrild 1) and two males (Gjerrild 5 + 8), harbouring typical Neolithic K2a and HV0 mtDNA haplogroups, but also a rare basal variant of the R1b1 Y-chromosomal haplogroup. Genome-wide analyses demonstrate that these people had a significant Yamnaya-derived (i.e. steppe) ancestry component and a close genetic resemblance to the Corded Ware (and related) groups that were present in large parts of Northern and Central Europe at the time. Assuming that the Gjerrild skeletons are genetically representative of the population of the SGC in broader terms, the transition from the local Neolithic Funnel Beaker Culture (TRB) to SGC is not characterized by demographic continuity. Rather, the emergence of SGC in Denmark was part of the Late Neolithic and Early Bronze Age population expansion that swept across the European continent in the 3rd millennium BCE, resulting in various degrees of genetic replacement and admixture processes with previous Neolithic populations.
|
|
| 3. |
- Feng, Shaohong, et al.
(author)
-
Dense sampling of bird diversity increases power of comparative genomics
- 2020
-
In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 587:7833
-
Journal article (peer-reviewed)abstract
- Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity(1-4). Sparse taxon sampling has previously been proposed to confound phylogenetic inference(5), and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363 genomes from 92.4% of bird families-including 267 newly sequenced genomes produced for phase II of the Bird 10,000 Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater numbers than has previously been possible and to recognize genomic novelties in particular bird lineages. The densely sampled alignment provides a single-base-pair map of selection, has more than doubled the fraction of bases that are confidently predicted to be under conservation and reveals extensive patterns of weak selection in predominantly non-coding DNA. Our results demonstrate that increasing the diversity of genomes used in comparative studies can reveal more shared and lineage-specific variation, and improve the investigation of genomic characteristics. We anticipate that this genomic resource will offer new perspectives on evolutionary processes in cross-species comparative analyses and assist in efforts to conserve species. A dataset of the genomes of 363 species from the Bird 10,000 Genomes Project shows increased power to detect shared and lineage-specific variation, demonstrating the importance of phylogenetically diverse taxon sampling in whole-genome sequencing.
|
|
| 4. |
- Gelabert, Pere, et al.
(author)
-
Evolutionary History, Genomic Adaptation to Toxic Diet, and Extinction of the Carolina Parakeet
- 2020
-
In: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 30:1, s. 108-114
-
Journal article (peer-reviewed)abstract
- As the only endemic neotropical parrot to have recently lived in the northern hemisphere, the Carolina parakeet (Conuropsis carolinensis) was an iconic North American bird. The last surviving specimen died in the Cincinnati Zoo in 1918 [1]. The cause of its extinction remains contentious: besides excessive mortality associated to habitat destruction and active hunting, their survival could have been negatively affected by its range having become increasingly patchy [2] or by the exposure to poultry pathogens [3, 4]. In addition, the Carolina parakeet showed a pre-dilection for cockleburs, an herbaceousplant that contains a powerful toxin, carboxyatractyloside, or CAT [5], which did not seem to affect them but made the birds notoriously toxic to most predators [3]. To explore the demographic history of this bird, we generated the complete genomic sequence of a preserved specimen held in a private collection in Espinelves (Girona, Spain), as well as of a close extant relative, Aratinga solstitialis. We identified two non-synonymous genetic changes in two highly conserved proteins known to interact with CAT that could underlie a specific dietary adaptation to this toxin. Our genomic analyses did not reveal evidence of a dramatic past demographic decline in the Carolina parakeet; also, its genome did not exhibit the long runs of homozygosity that are signals of recent inbreeding and are typically found in endangered species. As such, our results suggest its extinction was an abrupt process and thus likely solely attributable to human causes.
|
|
| 5. |
- Gopalakrishnan, Shyam, et al.
(author)
-
The population genomic legacy of the second plague pandemic
- 2022
-
In: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 32:21, s. 4743-4751.e6
-
Journal article (peer-reviewed)abstract
- Human populations have been shaped by catastrophes that may have left long-lasting signatures in their genomes. One notable example is the second plague pandemic that entered Europe in ca. 1,347 CE and repeatedly returned for over 300 years, with typical village and town mortality estimated at 10%–40%.1 It is assumed that this high mortality affected the gene pools of these populations. First, local population crashes reduced genetic diversity. Second, a change in frequency is expected for sequence variants that may have affected survival or susceptibility to the etiologic agent (Yersinia pestis).2 Third, mass mortality might alter the local gene pools through its impact on subsequent migration patterns. We explored these factors using the Norwegian city of Trondheim as a model, by sequencing 54 genomes spanning three time periods: (1) prior to the plague striking Trondheim in 1,349 CE, (2) the 17th–19th century, and (3) the present. We find that the pandemic period shaped the gene pool by reducing long distance immigration, in particular from the British Isles, and inducing a bottleneck that reduced genetic diversity. Although we also observe an excess of large FST values at multiple loci in the genome, these are shaped by reference biases introduced by mapping our relatively low genome coverage degraded DNA to the reference genome. This implies that attempts to detect selection using ancient DNA (aDNA) datasets that vary by read length and depth of sequencing coverage may be particularly challenging until methods have been developed to account for the impact of differential reference bias on test statistics.
|
|
| 6. |
- Liu, Shanlin, et al.
(author)
-
Ancient and modem genomes unravel the evolutionary history of the rhinoceros family
- 2021
-
In: Cell. - : Elsevier. - 0092-8674 .- 1097-4172. ; 184:19, s. 4874-4885.e16
-
Journal article (peer-reviewed)abstract
- 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. This early Miocene (similar to 16 million years ago [mya]) split post-dates the land bridge formation between the Afro-Arabian and Eurasian landmasses. Our analyses also show that while rhinoceros genomes in general exhibit low levels of genome-wide diversity, heterozygosity is lowest and inbreeding is highest in the modern species. These results suggest that while low genetic diversity is a long-term feature of the family, it has been particularly exacerbated recently, likely reflecting recent anthropogenic-driven population declines.
|
|
| 7. |
- Margaryan, Ashot, et al.
(author)
-
Low-Pressure MWPC System for the detection of Alpha-Particles and Fission Fragments
- 2010
-
In: Armenian Journal of Physics. - 1829-1171. ; 3:4, s. 282-291
-
Journal article (peer-reviewed)abstract
- A low-pressure, position-sensitive, multi-wire proportional chamber (LPMWPC) system with an active area 12×12 cm 2 for the detection of heavy nuclear fragments, has been developed for use in tagged photon beam experiments. The LPMWPC system can be operated in single as well as double step operational modes. In the case of double step operational mode with a high gas amplification factor, signals from α-particles reside well above the electronic noise. Typical energy loss spectra of alpha particles and fission fragments (FF) obtained from a 252 Cf source are shown and discussed. The pulse height distributions of α-particles have a Landau distribution shape, while the pulse height distribution of FFs differs from Gaussian shape. It has long tails at both low-and high-energy sides. The average pulse height ratio of alpha particles and FF's is close to the theoretical value and amounts to about 1/80.
|
|
| 8. |
- Margaryan, Ashot, et al.
(author)
-
Population genomics of the Viking world
- 2020
-
In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 585:7825, s. 390-396
-
Journal article (peer-reviewed)abstract
- The maritime expansion of Scandinavian populations during the Viking Age (about ad 750–1050) was a far-flung transformation in world history1,2. Here we sequenced the genomes of 442 humans from archaeological sites across Europe and Greenland (to a median depth of about 1×) to understand the global influence of this expansion. We find the Viking period involved gene flow into Scandinavia from the south and east. We observe genetic structure within Scandinavia, with diversity hotspots in the south and restricted gene flow within Scandinavia. We find evidence for a major influx of Danish ancestry into England; a Swedish influx into the Baltic; and Norwegian influx into Ireland, Iceland and Greenland. Additionally, we see substantial ancestry from elsewhere in Europe entering Scandinavia during the Viking Age. Our ancient DNA analysis also revealed that a Viking expedition included close family members. By comparing with modern populations, we find that pigmentation-associated loci have undergone strong population differentiation during the past millennium, and trace positively selected loci—including the lactase-persistence allele of LCT and alleles of ANKA that are associated with the immune response—in detail. We conclude that the Viking diaspora was characterized by substantial transregional engagement: distinct populations influenced the genomic makeup of different regions of Europe, and Scandinavia experienced increased contact with the rest of the continent.
|
|
| 9. |
- Mühlemann, Barbara, et al.
(author)
-
Diverse variola virus (smallpox) strains were widespread in northern Europe in the Viking Age
- 2020
-
In: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 369:6502
-
Journal article (peer-reviewed)abstract
- Smallpox, one of the most devastating human diseases, killed between 300 million and 500 million people in the 20th century alone. We recovered viral sequences from 13 northern European individuals, including 11 dated to ~600-1050 CE, overlapping the Viking Age, and reconstructed near-complete variola virus genomes for four of them. The samples predate the earliest confirmed smallpox cases by ~1000 years, and the sequences reveal a now-extinct sister clade of the modern variola viruses that were in circulation before the eradication of smallpox. We date the most recent common ancestor of variola virus to ~1700 years ago. Distinct patterns of gene inactivation in the four near-complete sequences show that different evolutionary paths of genotypic host adaptation resulted in variola viruses that circulated widely among humans.
|
|
| 10. |
- Sánchez-Barreiro, Fátima, et al.
(author)
-
Historic Sampling of a Vanishing Beast: Population Structure and Diversity in the Black Rhinoceros
- 2023
-
In: Molecular biology and evolution. - 0737-4038 .- 1537-1719. ; 40:9
-
Journal article (peer-reviewed)abstract
- The black rhinoceros (Diceros bicornis L.) is a critically endangered species historically distributed across sub-Saharan Africa. Hunting and habitat disturbance have diminished both its numbers and distribution since the 19th century, but a poaching crisis in the late 20th century drove them to the brink of extinction. Genetic and genomic assessments can greatly increase our knowledge of the species and inform management strategies. However, when a species has been severely reduced, with the extirpation and artificial admixture of several populations, it is extremely challenging to obtain an accurate understanding of historic population structure and evolutionary history from extant samples. Therefore, we generated and analyzed whole genomes from 63 black rhinoceros museum specimens collected between 1775 and 1981. Results showed that the black rhinoceros could be genetically structured into six major historic populations (Central Africa, East Africa, Northwestern Africa, Northeastern Africa, Ruvuma, and Southern Africa) within which were nested four further subpopulations (Maasailand, southwestern, eastern rift, and northern rift), largely mirroring geography, with a punctuated north–south cline. However, we detected varying degrees of admixture among groups and found that several geographical barriers, most prominently the Zambezi River, drove population discontinuities. Genomic diversity was high in the middle of the range and decayed toward the periphery. This comprehensive historic portrait also allowed us to ascertain the ancestry of 20 resequenced genomes from extant populations. Lastly, using insights gained from this unique temporal data set, we suggest management strategies, some of which require urgent implementation, for the conservation of the remaining black rhinoceros diversity.
|
|
