Papaya

The transgenic papaya “SunUp” was developed in the 1990s and was widely publicized because of its ability to resist the papaya ringspot virus. Although researchers from the Ming group had identified the genomic sequence of SunUp by 2008, it was unclear where the transgenic insertions were and what effect they had. A new study has now identified these changes and how they influence the transgenic plants. 

A genetic study of papaya sex chromosomes reveals that the hermaphrodite version of the plant, which is of most use to growers, arose as a result of human selection, most likely by the ancient Maya some 4,000 years ago.

The study, reported in the journal Genome Research, homes in on a region of papaya’s male sex chromosome that, the study indicates, gave rise to the hermaphrodite plants.