WASHINGTON — Papayas have extra copies of
genes that make them sweet and nutritious, researchers reported
recently in a study that can help shed light on how flowering
plants evolved.
They published the complete genetic sequence
of the "SunUp" papaya, a tree genetically engineered to be virus
resistant.
Writing in the journal Nature, they said the
plant has fewer genes than the more thoroughly studied weed
Arabdopsis, yet has a longer DNA sequence.
They believe they have pinpointed genes
responsible for helping tree-like plants evolve, and genes that
helped make it smell and taste so good, attracting animals and
people to spread its seeds. Papayas have extra genes that appear
to code for these aromas and for storing starch, presumably in
the fruit.
"This also foreshadows what we might expect
to discover in the genomes of other fragrant-fruited trees, as
well as plants with striking fragrance of leaves (herbs),
flowers or other organs," Maqsudul Alam of the University of
Hawaii and colleagues wrote.
"Papaya is ranked first on nutritional scores among 38 common
fruits, based on the percentage of the United States Recommended
Daily Allowance for vitamin A, vitamin C, potassium, folate,
niacin, thiamine, riboflavin, iron and calcium, plus fiber,"
they wrote. – Reuters
