Distribution and ice-ages
Global distribution of Arabidopsis lyrata complex and distribution of ice-sheets (in blue) at time of last glacial maximum c.15, 000 years ago. Solid line Arabidopsis lyrata ssp. lyrata, broken solid line Arabidopsis lyrata ssp. petraea, dotted line Arabidopsis lyrata ssp. kamchatica © S Ansell
The A. lyrata group is distribution in cool temperate areas that circle the Arctic. This range mainly coincides with areas that were covered in ice during the last ice-age 15,000 years ago. Regular cycles of cooling (glaciations) and warming (as currently) have occurred over the last 2.5 million years (the Pleistocene).
Studies of DNA sequence differences indicate that the subspecies have diverged during this climatically unstable period, most-likely due to repeated population extinctions and geographic isolation, with populations surviving in separate locations near to the ice sheets margins.