Bad Karma can ruin palm oil crops

Cloned trees that lack DNA methylation produce poor fruit

Oil palm plantation

PALM PRESSER  Otherwise identical cloned oil palms (a plantation shown) can develop a flaw that ruins crops. Scientists have discovered the source of the flaw.

Meilina Ong-Abdullah/MPOB

Palm oil producers thought they had licked shortages of edible oil and biofuel in the 1980s, when they learned to make genetically identical copies of high oil-yielding palms. But when the cloned palms matured, some plants made shriveled fruits with very little oil. Exactly how these dry, “mantled” fruits spawned from twins of oil-gushing palms has been a mystery ever since.

Oil-barren plants are a result of Bad Karma, researchers report online September 9 in Nature. That’s not to say shriveled fruit is retribution for past actions. Karma in palm oil plants is a “jumping gene,” or transposon, a selfish bit of DNA that copies and inserts itself in a host’s DNA.  

Palms usually weigh the transposon down by attaching molecules called methyl groups to the transposon’s DNA.

LUCK OR EPIGENETICS A tweak to chemical tags on DNA causes normally plump, oily palm fruit (top) to instead make shriveled, or mantled, fruit (bottom) with little oil. Martienssen Lab/CSHL
 Such DNA methylation, known as an epigenetic mark, affects gene activity without changing the gene itself. In dry palms, much of the methylation is missing, Robert Martienssen of Cold Spring Harbor Laboratory in New York and colleagues discovered. Cloning may accidentally remove the methyl groups from the Karma DNA in some sprouts.

The researchers dubbed Karma DNA that is heavily laden with methylation as Good Karma because it coincides with oily fruit; the methylation-impoverished transposons are Bad Karma, because they ruin crops. Genetic tests for Good and Bad Karma may help growers identify bad clones early and weed them out.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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