The genome sequence of carrot (Daucus carota L.) [see attached article] is the first completed for a species in the family Apiaceae. This evolutionary genomics study furthers our knowledge of the evolution of the important euasterid II clade. Analyzing the whole-genome sequence of carrot allowed for identification of a gene is likely to regulate the accumulation of carotenoids in the root. This knowledge will be important in the designing of genetically modified foods having more carotenoids in the root (to aid in nutrition and undernourished populations in third-world countries)––that is, if members of the Environmentalists Cult will cease and desist with their hysterical objections to GMO foods.
The attached study reports a high-quality chromosome-scale assembly and analysis of the carrot genome. Authors characterized two new polyploidization events––both occurring after the divergence of carrot from members of the order Asterales. This sequence knowledge clarifies the evolutionary scenario before, and after, radiation of the two main asterid clades. Large- and small-scale lineage-specific duplications were discovered to have contributed to the expansion of gene families, including those with roles in flowering time, defense response, flavor, and pigment accumulation. Undoubtedly, MANY dozens of cytochrome P450 (CYP) genes are involved in these processes. Authors identified a candidate gene, DCAR_032551, that causes carotenoid accumulation (the Y gene) in carrot tap-root and is co-expressed with several isoprenoid biosynthetic genes. The primary mechanism regulating carotenoid accumulation in carrot tap-root is not at the biosynthetic level. Authors hypothesize that DCAR_032551 regulates upstream photosystem development and functional processes, including photomorphogenesis and root de-etiolation. De-etoliation is the transition of seedlings from below-ground growth to an above-ground growth form. Interestingly, by imputation, authors speculate that further divergence between carrot and lettuce, both members of the euasterid II clade, likely occurred ~72 million years ago.
[Interestingly, this message is being brought to you in font that is the color of ‘Carrot’.] 😉 (at least the original post was that color, ed, 🙁 )
Nat Genet June 2o16; 48: 657-666 (article) and pp 589-590 (ed.)