Principles of DArT
What is a DArT marker?
A DNA segment, present or absent in a defined genomic representation, depending on the individual genotype.
What is a genomic representation?
A specific fraction of the genome, produced in a reproducible manner by applying to the genome a complexity reduction method. Genomic representations used in DArT usually comprise 0.1 to 10% of the genome depending on the initial complexity of the organism. There are many possible methods to produce a genomic representation of the appropriate complexity.
What is the molecular basis of polymorphism?
Any change that causes the defined segment to be scored as present or absent in the representation, for example: SNP or differential methylation in restriction sites used to generate the representation, insertion or deletion in the genomic sequence corresponding to the marker (including transposons).
How to score?
By hybridisation to a probe homologous to the marker. Many different platforms can be used for scoring. At this stage a DNA-microarray platform is being used by most licensees, but other platforms can be contemplated. CAMBIA encourages improvement of the technology for multiple platforms by making it available via the non-exclusive Genetic Resource Indexing Technology BiOS License.
Where are the markers in the genome?
In principle they should be anywhere; data available in rice and barley suggest this is correct.