A team of researchers headed by Professor Richard Michelmore, director of the Genomic Center at the University of California, Davies, published in Nature Communications, the assembled genome of lettuce (Lactuca sativa), which is the most valuable fresh vegetable and one of the 10 most valuable crops in the US with a market value of over $ 2.4 billion. Lactuca sativa is representative of the large and highly successful from evolutional point of view family of Compositae, including a variety of representatives such as daisy, sunflower, ragweed, and the star thistle. The assembled genome, representing the stacked puzzle of millions of DNA sequences, is a valuable tool that enables scientists to explore the many species of Compositae, incorporating various aspects, both from an evolutionary point of view and from a functional point of view. Prof. Michelmore says: “This is particularly significant because Compositae is the most successful family of flowering plants on earth in terms of the number of species and environments inhabited”. According to the scientists, the success of this family may be due to the genome triplication, which happened during its 48 million years of evolution, as evidenced by the fact that about a quarter of the genome, including about 30% of the identified genes appear in multiple related regions. Events involving genomic duplication or triplication, as is the case, can give plant species an evolutionary advantage in colonizing new environments.
Reyes-Chin-Wo, S. et al. Genome assembly with in vitro proximity ligation data and whole-genome triplication in lettuce. Nat. Commun. 8, 14953 doi: 10.1038/ncomms14953 (2017)