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Porous genomes and the nature of plant species differences in a pair of hybridizing silence species

Titel Englisch Porous genomes and the nature of plant species differences in a pair of hybridizing silence species
Gesuchsteller/in Widmer Alexander
Nummer 116455
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut für Integrative Biologie Departement Umweltwissenschaften ETHZ
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Botanik
Beginn/Ende 01.07.2007 - 31.08.2010
Bewilligter Betrag 391'678.00
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Alle Disziplinen (3)

Disziplin
Botanik
Molekularbiologie
Genetik

Keywords (6)

adaptation; hybridization; introgression; reproductive isolation; selection; species boundary

Lay Summary (Englisch)

Lead
Lay summary
Hybridization is a widespread phenomenon in plants that has profound consequences for genome organization and evolution, may lead to speciation, and creates opportunities for adaptive evolution. Recent developments in population genetics and genomics allow to study how species diverge and provide access to genome-wide analyses of hybridization and gene introgression. Such studies will reveal how porous plant genomes are and what factors determine the extent of genome porosity.This research project investigates hybridization and introgression in a Silene species pair, Silene latifolia and S. dioica. We have previously shown that hybrid zones between these species act as bridges to gene-flow and that gene introgression is extensive, but varies substantially between different parts of the species genomes. In this project we ask:1) Does divergence in gene expression precede sequence divergence?It has long been hypothesized that divergence and adaptation over short evolutionary time, for example between sister-species, may often proceed by divergence in gene expression, rather than sequence divergence. This prediction has rarely been tested. 2) Is genetic divergence between Silene species due to natural selection ?Species divergence, no matter whether it is due to sequence or gene expression divergence, can be a consequence of either neutral processes, such as random genetic drift, or can be due to natural selection. The two scenarios are best distinguished by investigating patterns of divergence on a genome-wide scale, because neutral processes affect the entire genome, whereas natural selection acts on individual genes or genomic regions. The identification of a subset of genes or genomic regions that show significantly higher divergence than expected under a scenario of neutral divergence would thus provide strong evidence for a role of natural selection in species divergence3) How do chromosomal rearrangements affect genome porosity?Species differences may accumulate in genomic regions that are characterized by chromosomal rearrangements, because these prevent recombination and may thus shelter genomic regions from introgression.This research project will likely provide new insights into the genetic basis of species differences, genome-wide patterns of divergence between closely related, ecologically diverged plant species, and into the importance of natural selection versus chromosomal rearrangements for genome porosity and the maintenance of species boundaries. These issues are of fundamental biological interest, but may also be of applied relevance in the context of gene-flow between genetically modified (GM) crops and their wild relatives.
Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

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141260 Genomic divergence in plants: exploring the consequences of ecological adaptation for plant divergence and speciation 01.05.2012 Projektförderung (Abt. I-III)

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