Polyploidization
is a widespread phenomenon among plants and is considered a major
speciation mechanism. Polyploids have a high degree of immediate
post-zygotic reproductive isolation from their progenitors, as
backcrossing to either parent will produce mainly nonviable progeny.
This reproductive barrier is called triploid block and is caused by
malfunction of the endosperm. Nevertheless, the main route to polyploid
formation is via unreduced gametes and unstable triploid progeny,
suggesting that there are ways to overcome the triploid block. Until
recently, neither the formation of unreduced gametes nor the triploid
block were understood mechanistically. We aim at elucidating the
mechanisms contributing to polyploid formation and their impact on
plant speciation.
Related
Publications:
Erilova, E., Brownfield, L., Exner, V., Rosa, M., Twell, D., Mittelsten
Scheid, O., Hennig, L., Köhler, C. (2009) Imprinting of the Polycomb
Group Gene MEDEA Serves as a Ploidy Sensor in Arabidopsis. PLoS Genet.
5:e1000663. (
Medline)