August 30, 2010

Scientists Get To The Core Of The Apple Genome

One of the world's most popular fruits, the apple, has been genetically sequenced by scientists, which could lead to producing crisper, juicier and more flavorsome crops in the future.

Scientists, reporting in the journal Nature Genetics, said the genome comprises 600 million base pairs, or "rungs" of DNA in the ladder of genetic code.

The apple is a member of the Rosaceae family -- rose family -- which includes about 33 percent of all flowering plants. Other fruit species, like the peach, raspberry and strawberry, are included in this family.

Although there are differences between these fruit plants, large areas of the apple's DNA are found in these other fruit species, according to the study. However, the genetic material is ordered much differently.

The apple is a close relative to the pear, and they both share the same 17 chromosomes, but others share only seven to nine chromosomes with apples.

Scientists suggest that based on these similarities, there was an "apple ancestor" before the great extinction around 50 to 65 million years ago, when the dinosaurs were wiped out at the end of the Cretaceous era.

"By duplicating almost all of its genome, apples now have very different fruit characteristics to related plants such as peaches, raspberries and strawberries," Sue Gardiner, a scientist at New Zealand Plant and Food Research, who took part in the study, told the AFP news agency.

"This suggests that a major environmental event forced certain species, including apple, to evolve for survival," Gardiner added.

Thirteen institutions from five countries took part in the genetic sequencing effort. The team successfully cracked open the genetic code of a "Golden Delicious."

Scientists are rushing to sequence genetic codes of several foods, which could help pinpoint inherited traits for boosting crop yields, flavor and other characteristics.

Scientists at New Zealand's Plant and Food Research are using genetic data to produce new apple strains, including a red-fleshy fruit that has higher levels of anthocyanins, a type of antioxidant.

British geneticists last week published a draft of a benchmark variety of wheat. Wheat accounts for 30 percent of global grain production. However, supplies of the food staple cannot keep up with the surging population growth, and water stress caused by climate change and the emergence of a deadly strain of fungus called stem rust are hurting wheat yields.


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