The strategy adopted by the group involves integrating the available sequence data for oilseed rape with that of its ancestral progenitors, and also that of a more distantly-related species for which high-quality genome sequence data is available, in this case the model plant Arabidopsis thaliana.
Instead of trying to sequence the DNA, the team focussed on the RNA transcribed from the DNA when the genetic code is expressed. The complete set of all of this transcribed RNA is known as the transcriptome.
TGAC used the Illumina GAII platform for the study, producing a series of consistently high quality sequence datasets from expressed genes.
The team analysed the transcriptome in juvenile leaves, which gives an overview of all of the genes that are expressed in that tissue. Using the sequence variation the researchers were able to construct genetic linkage maps in oilseed rape, eventually identifying over 23,000 markers. This allowed them to align the oilseed rape genome with that of Arabidopsis thaliana and also to sequence data from oilseed rape's two progenitor species.
This method of dissecting the genome of polyploid crops is likely to be equally applicable to other important crops. Bread wheat is a prime candidate for this, using the model grass Brachypodium distachyon in the place of Arabidopsis.
"Dissecting the genome of oilseed rape like this opens up the possibility of using predictive breeding techniques that will really help with the production of improved varieties" said Prof. Bancroft.
|Contact: Andrew Chapple|
Norwich BioScience Institutes