Changes in Anthocyanin Production during Domestication of .

Mandarin (), citron (), and pummelo () are important species of the genus and parents of the interspecific hybrids that constitute the most familiar commercial varieties of : sweet orange, sour orange, clementine, lemon, lime, and grapefruit. Citron produces anthocyanins in its young leaves and flowers, as do species in genera closely related to , but mandarins do not, and pummelo varieties that produce anthocyanins have not been reported. We investigated the activity of the gene, which encodes a MYB transcription factor controlling anthocyanin biosynthesis, in different accessions of a range of species and in domesticated cultivars. A white mutant of lemon lacks functional alleles of , demonstrating that plays an essential role in anthocyanin production in Almost all the natural variation in pigmentation by anthocyanins in species can be explained by differences in activity of the gene, caused by point mutations and deletions and insertions of transposable elements. Comparison of the allelic constitution of in different species and cultivars also helps to clarify many of the taxonomic relationships in different species of , confirms the derivation of commercial varieties during domestication, elucidates the relationships within the subgenus , and allows a new genetic classification of mandarins.