Research conducted by the Wageningen University and Research (WUR) and BGI Genomics has described the special history of lettuce in detail through their DNA analysis of 445 types of lettuce.

The Centre for Genetic Resource, the Netherlands (CGN), the Dutch gene bank and part of WUR, manages a collection of 2,500 lettuce types, the largest, most complete, and best-documented lettuce collection in the world. Together with BGI, work is being done to determine the genome sequence for all 2,500 types. The results from the first 445 types of lettuce show the origins and breeding history of the crop.

The research revealed that the first wild plants were modified for cultivation 6,000 years ago in the Caucasus. These first lettuces were harvested for seeds to extract oil, and the ancient Greek and Romans further bred these plants (at that time, they still had thorns on the leaves) to be used as leafy vegetables. The modern varieties of cultivated lettuces mostly resemble their wild predecessor Lactuca serriola from the Caucasus. The study also determined the point at which the more recent iceberg lettuce diverged from "ancient" butterhead lettuce in the genetic material of the wild L. virosa.

For more details, read the article in WUR News or the paper's abstract in Nature Genetics.