Polyploidy: Genetics, Evolution and Ecology
Dilkes, Brian , Josefsson, Caroline , Henry, Isabelle , Comai, Luca .
The F1 lethality in interploidy and interspecies hybrids of Arabidopsis are controlled by the same genetic network.
Speciation is often associated with changes in chromosome or genome copy number. This shift in gene dosage can affect reproductive isolation via postzygotic lethality. Using natural variation, induced mutations and karyotypic variants in the genus Arabidopsis we have identified dosage-sensitive genetic networks that affect variation in F1 viability in crosses between species and between karyotypes within species. Dissection of the genetic architecture of this variability, via QTL and mutant analyses, has identified both maternally and paternally derived genetic controls. We have molecularly identified single genes capable of modulating F1 hybrid lethality, such as the TTG2 transcription factor, and demonstrated that identical genetic mechanisms act in interspecies hybrids and in interploidy hybrids of the same species. Gene dosage sensitivity is a property expected of members of protein complexes and genetic networks. Genetic analyses confirm that the maternal control of F1 lethality in both the interspecies and interploidy crosses are profoundly affected by epistasis. Furthermore, the genotype of the maternal sporophyte strongly impacts F1 lethality. The coordination of growth between the maternal sporophyte and the endosperm appears to be the developmental process critical to hybrid survival. This demonstrates that both interploidy and interspecies barriers are sensitive to the doses of the same factors and suggests molecular and developmental mechanisms affecting post-zygotic isolation in angiosperm speciation.
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1 - UC Davis, Genome Center, Davis, CA, USA
2 - University of Washington, Biology, Seattle, WA, USA
3 - UC Davis, Genome Center and Section of Plant Biology, Davis, CA, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Room 2/Woodward
Date: Tuesday, July 29th, 2008
Time: 2:00 PM