| 1. |
- Gounot, Jean Sébastien, et al.
(författare)
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High Complexity and Degree of Genetic Variation in Brettanomyces bruxellensis Population
- 2020
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 12:6, s. 795-807
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide characterization of genetic variants of a large population of individuals within the same species is essential to have a deeper insight into its evolutionary history as well as the genotype-phenotype relationship. Population genomic surveys have been performed in multiple yeast species, including the two model organisms, Saccharomyces cerevisiae and Schizosaccharomyces pombe. In this context, we sought to characterize at the population level the Brettanomyces bruxellensis yeast species, which is a major cause of wine spoilage and can contribute to the specific flavor profile of some Belgium beers. We have completely sequenced the genome of 53 B. bruxellensis strains isolated worldwide. The annotation of the reference genome allowed us to define the gene content of this species. As previously suggested, our genomic data clearly highlighted that genetic diversity variation is related to ploidy level, which is variable in the B. bruxellensis species. Genomes are punctuated by multiple loss-of-heterozygosity regions, whereas aneuploidies as well as segmental duplications are uncommon. Interestingly, triploid genomes are more prone to gene copy number variation than diploids. Finally, the pangenome of the species was reconstructed and was found to be small with few accessory genes compared with S. cerevisiae. The pangenome is composed of 5,409 ORFs (open reading frames) among which 5,106 core ORFs and 303 ORFs that are variable within the population. All these results highlight the different trajectories of species evolution and consequently the interest of establishing population genomic surveys in more populations.
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| 2. |
- Söderberg, Jonas, et al.
(författare)
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The Genome of Setaria digitata: A Cattle Nematode Closely Related to Human Filarial Parasites
- 2020
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 12, s. 3971-3976
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Tidskriftsartikel (refereegranskat)abstract
- Here we present the draft genome sequence of Setaria digitata, a parasitic nematode affecting cattle. Due to its similarity to Wuchereria bancrofti, the parasitic nematode that causes lymphatic filariasis in humans, S. digitata has been used as a model organism at the genomic level to find drug targets which can be used for the development of novel drugs and/or vaccines for human filariasis. Setaria digitata causes cerebrospinal nematodiasis in goats, sheep, and horses posing a serious threat to livestock in developing countries. The genome sequence of S. digitata will assist in finding candidate genes to use as drug targets in both S. digitata and W. bancrofti. The assembled draft genome is similar to 90 Mb long and contains 8,974 genomicscaffolds with a G+C content of 31.73%.
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| 3. |
- Wang, Xi, 1990-, et al.
(författare)
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Demography and Natural Selection Have Shaped Genetic Variation in the Widely Distributed Conifer Norway Spruce (Picea abies)
- 2020
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Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653 .- 1759-6653. ; 12:2, s. 3803-3817
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Tidskriftsartikel (refereegranskat)abstract
- Under the neutral theory, species with larger effective population size are expected to harbor higher genetic diversity. However, across a wide variety of organisms, the range of genetic diversity is orders of magnitude more narrow than the range of effective population size. This observation has become known as Lewontin's paradox and although aspects of this phenomenon have been extensively studied, the underlying causes for the paradox remain unclear. Norway spruce (Picea abies) is a widely distributed conifer species across the northern hemisphere, and it consequently plays a major role in European forestry. Here, we use whole-genome resequencing data from 35 individuals to perform population genomic analyses in P. abies in an effort to understand what drives genome-wide patterns of variation in this species. Despite having a very wide geographic distribution and an corresponding enormous current population size, our analyses find that genetic diversity of P. abies is low across a number of populations (pi = 0.0049 in Central-Europe, pi = 0.0063 in Sweden-Norway, pi = 0.0063 in Finland). To assess the reasons for the low levels of genetic diversity, we infer the demographic history of the species and find that it is characterized by several reoccurring bottlenecks with concomitant decreases in effective population size can, at least partly, provide an explanation for low polymorphism we observe in P. abies. Further analyses suggest that recurrent natural selection, both purifying and positive selection, can also contribute to the loss of genetic diversity in Norway spruce by reducing genetic diversity at linked sites. Finally, the overall low mutation rates seen in conifers can also help explain the low genetic diversity maintained in Norway spruce.
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