| 1. |
- Song, Kai, 1988-
(författare)
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Divergence, selection, demographic history and conservation genomics of sibling bird species in boreal forest in Northern Eurasia and the Qinghai-Tibetan Plateau
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I used two pairs of sibling boreal forest bird species to study divergence, selection, demographics, and conservation in northern Eurasia and the Qinghai-Tibetan Plateau at the microsatellite level (chapter 1) and whole genome level (chapters 2, 3, 4 and 5). In chapter 1, which is the first study to describe genetic diversity of the Sichuan Jay, I used microsatellite markers to estimate genetic differentiation in Sichuan Jay and Siberian Jay populations. The results showed similar levels of genetic variability, strong population structure, and high genetic differentiation between the two species and among different populations. In chapter 2, I used demographic analyses, and found that the Chinese Grouse has experienced substantial changes in population size from the beginning of the last interglacial, with a peak just before the last glacial maximum. The results inferred from the whole genome sequencing and species distribution models support a history of population size fluctuations. In chapter 3 to 5, I used population genomic methods to explore genomic variation, demographic divergence, local adaptation, and inbreeding from 29 whole genome re-sequenced individuals of Chinese Grouse and Hazel Grouse. I found strong evidence for population structure, changing demographic histories, and varying inbreeding levels and genetic load within both species. In Chinese Grouse, an isolated population in the northern part of the species range showed the lowest genetic diversity, high pairwise FST, high LD decay, higher inbreeding and genetic load compared to two other populations. In Hazel Grouse, there were strong population differences and inbreeding levels among the three populations, especially among the Swedish and German populations. The Swedish population likely lost genetic diversity during the re-colonization of the boreal forests in Scandinavia after the last glaciation. Analyses of genetic load showed that purifying selection of mildly deleterious mutations has been more efficient in Hazel Grouse, a species with a larger population size and range compared to Chinese Grouse. However, when I compared the genetic load as the ratio between highly deleterious loss-of-function mutations and synonymous mutations for Chinese Grouse and Hazel Grouse, purifying selection did not seem to have a large effect. My findings show that small, isolated and fragmented populations of forests birds loose genetic variation and may thereby become vulnerable to future challenges and also that populations may track past habitat changes and adapt to local conditions.
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| 2. |
- van Zuydam, Natalie R., et al.
(författare)
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Genetic Predisposition to Coronary Artery Disease in Type 2 Diabetes Mellitus
- 2020
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Ingår i: Circulation. - : Lippincott Williams & Wilkins. - 2574-8300. ; 13:6, s. 640-648
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Coronary artery disease (CAD) is accelerated in subjects with type 2 diabetes mellitus (T2D).METHODS: To test whether this reflects differential genetic influences on CAD risk in subjects with T2D, we performed a systematic assessment of genetic overlap between CAD and T2D in 66 643 subjects (27 708 with CAD and 24 259 with T2D). Variants showing apparent association with CAD in stratified analyses or evidence of interaction were evaluated in a further 117 787 subjects (16 694 with CAD and 11 537 with T2D).RESULTS: None of the previously characterized CAD loci was found to have specific effects on CAD in T2D individuals, and a genome-wide interaction analysis found no new variants for CAD that could be considered T2D specific. When we considered the overall genetic correlations between CAD and its risk factors, we found no substantial differences in these relationships by T2D background.CONCLUSIONS: This study found no evidence that the genetic architecture of CAD differs in those with T2D compared with those without T2D.
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| 3. |
- Zhang, Wei, et al.
(författare)
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Observation of the proton emitter 11657La59
- 2022
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Ingår i: Communications Physics. - : Springer Science and Business Media LLC. - 2399-3650. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental “smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope 1165757116La59, 23 neutrons away from the only stable isotope 1395757139La82, is reported. 116La nuclei were synthesised in the fusion-evaporation reaction 58Ni(64Zn, p5n)116La and identified via their proton radioactivity using the mass spectrometer MARA (Mass Analysing Recoil Apparatus) and the silicon detectors placed at its focal plane. Comparisons of the measured proton energy (Ep = 718 ± 9 keV) and half-life (T1/2 = 50 ± 22 ms) with values calculated using the Universal Decay Law approach indicate that the proton is emitted with an orbital angular momentum l = 2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope (1175757117La60) while the proton-emission Q-value is lower. We propose this to be a possible signature for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. The observations of γ decays from isomeric states in 116La and 117La are also reported.
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