Loss of Karma transposon methylation underlies the mantled somaclonal variant of oil palm

The oil palm fruit ‘mantled’ abnormality is a somaclonal variant that markedly reduces yield; here, a genome-wide DNA methylation analysis finds that hypomethylation of a single Karma family retrotransposon embedded in a homeotic gene intron is common to all mantled clones and is associated with aberrant splicing and termination of the gene transcript, and that loss of methylation predicts a loss of oil palm yield.