Arabidopsis lyrata belongs to family Brassicaceae and is closely related to the model plant species Arabidopsis thaliana. It is believed to have diverged from A. thaliana about 5 million years ago. Comparative mapping analysis by Kuittinen at al has shown that except for few large chromosomal rearrangements, there is almost complete colinearity between the genetic map of A. lyrata and A. thaliana.A. lyrata differs from A. thaliana in being self-incompatible and out-crossing.