| 1. |
- Gramlich, Susanne, et al.
(författare)
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A polygenic architecture with habitat-dependent effects underlies ecological differentiation in Silene
- 2022
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Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 235:4, s. 1641-1652
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Tidskriftsartikel (refereegranskat)abstract
- Ecological differentiation can drive speciation but it is unclear how the genetic architecture of habitat-dependent fitness contributes to lineage divergence. We investigated the genetic architecture of cumulative flowering, a fitness component, in second-generation hybrids between Silene dioica and Silene latifolia transplanted into the natural habitat of each species.We used reduced-representation sequencing and Bayesian sparse linear mixed models (BSLMMs) to analyze the genetic control of cumulative flowering in each habitat.Our results point to a polygenic architecture of cumulative flowering. Allelic effects were mostly beneficial or deleterious in one habitat and neutral in the other. Positive-effect alleles often were derived from the native species, whereas negative-effect alleles, at other loci, tended to originate from the non-native species.We conclude that ecological differentiation is governed and maintained by many loci with small, habitat-dependent effects consistent with conditional neutrality. This pattern may result from differences in selection targets in the two habitats and from environmentally dependent deleterious load. Our results further suggest that selection for native alleles and against non-native alleles acts as a barrier to gene flow between species.
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| 2. |
- Karrenberg, Sophie, et al.
(författare)
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Dedication : Christian Lexer (1971-2019)
- 2020
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : Royal Society. - 0962-8436 .- 1471-2970. ; 375:1806
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 3. |
- Liu, Xiaodong
(författare)
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Mechanisms of speciation in Silene
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A fundamental question in the field of evolutionary biology is how new species originate. Investigating speciation benefits from an integrated approach, which requires a solid understanding of ecology, reproductive biology, geographical distribution, underlying genetic architecture of reproductive isolation (RI), demographic history and genomic divergence. In this thesis, I studied the evolution of reproductive isolation in the sister species Silene dioica (L.) Clairv. and S. latifolia Poiret. The aims of the thesis are to investigate (1) the individual and cumulative contributions of extrinsic and intrinsic reproductive barriers between S. dioica and S. latifolia, (2) the genetic architecture of traits associated with reproductive barriers (3) the demographic history of lineage-split between the two species, (4) genomic patterns of divergence between the species.I found that multiple extrinsic pre- and postzygotic barriers resulting from ecological differentiation contributed most to total RI, while intrinsic barriers had substantial individual strength but contributed weakly to total RI. QTL mapping revealed evidence for genetic coupling of QTLs controlling traits associated with RI, although QTLs were overall widely distributed. QTLs related to sexually dimorphic traits were located on or near the pseudo-autosomal region of the sex chromosomes. The best-supported demographic model suggests heterogeneous population size and migration rates among genome-wide loci and points to the presence of barrier loci. Genomic divergence (measured using FST and dXY) was commonly accentuated around the middle of linkage groups and near QTLs for traits associated with reproductive barriers.In summary, the results in my thesis indicate that the speciation process is driven by multiple interacting and complex reproductive barriers. The genomic divergence landscape is shaped by interplay of the magnitude of gene flow, the strength and timing of selection, and other confounding factors such as genomic features.
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