Core business: Apple genome laid bare
Genetically sequencing the apple could lead to crisper, juicier and more flavorsome apple harvests.
Sun, Aug 29, 2010 at 02:29 PM
FRUIT FAMILY: The apple is a member of the Rosaceae family, which includes a third of all flowering plants, among them a broad variety of fruit species, such as the peach, raspberry, pear and strawberry. (Photo: ZUMA Press)
One of the world's most popular fruits, the apple, has been genetically sequenced, an exploit that could lead to crisper, juicier and more flavorsome harvests, scientists said Sunday.
The genome comprises 600 million base pairs, or "rungs" of DNA in the ladder of genetic code, they reported in the journal Nature Genetics.
The apple is a member of the Rosaceae family, which includes a third of all flowering plants, among them a broad variety of fruit species, such as the peach, raspberry, pear and strawberry.
Despite the differences between these fruit plants, they share strong similarities at the genetic level, for large stretches of the apple's DNA are found in the other species, the study said.
However, the genetic material is ordered quite differently.
The apple, like its close cousin the pear, has 17 chromosomes, but the others have only between seven and nine chromosomes.
Put together, this picture suggests that there was an "apple ancestor" before a divergence that occurred around 50 to 65 million years ago.
Intriguingly, this is in the same timeframe as the catastrophic event that wiped out the dinosaurs at the end of the Cretaceous era.
A commonly-aired theory pins the blame on a space rock that whacked into the Earth and ignited huge fires as it collided, kicking clouds of ash and dust that cooled the climate.
"By duplicating almost all of its genome, apples now have very different fruit characteristics to related plants such as peaches, raspberries and strawberries," said Sue Gardiner, a scientist at New Zealand Plant and Food Research, which took part in the study.
"This suggests that a major environmental event forced certain species, including apple, to evolve for survival."
Thirteen institutions in five countries took part in the venture, which cracked open the genetic code of a "Golden Delicious."
Agricultural scientists are racing to sequence the genetic code of leading sources of food, as this could help pinpoint inherited traits for boosting yields, resilience, flavor and other characteristics.
Once identified, the genes can be spliced into other strains, often by using traditional breeding methods rather than by genetic engineering.
New Zealand's Plant and Food are already using such data to produce new apple strains, including a red-flesh fruit that has higher levels of anthocyanins, an antioxidant.
Last week, British geneticists published a draft of a benchmark variety of wheat.
The grain accounts for 30 percent of global grain production and 20 percent of daily food calories.
Supplies of the staple, though, are clouded by the world's surging population growth, water stress caused by climate change and the emergence of a strain of deadly fungus called stem rust.
Copyright 2010 AFP Global Edition