Epigenetics: The karma of oil palms.

Abstract

Despite their clonal origin, some oil palm trees develop fruits that give almost no oil. It emerges that the number of methyl groups attached to a DNA region called Karma determine which plants are defective. See Letter p.533 A flower and fruit abnormality known as 'mantled' can develop in some agricultural oil palm cultivars derived from tissue culture and the resulting mantled palms can become unproductive. Mantling is widely regarded as an epigenetic trait, but has not been fully explained. Meilina Ong-Abdullah et al. have undertaken a genome-wide, unbiased, DNA methylation analysis to look for loci epigenetically associated with the mantled phenotype. They find that hypomethylation of a single Karma family retrotransposon embedded in the intron of a homeotic gene is common to all mantled clones and associated with aberrant splicing and termination of the gene transcript. Loss of methylation — dubbed the Bad Karma epiallele — predicts a loss of oil palm yield and this property should enable screening for higher-performing clones at the plantlet stage.