GM Papaya — ʻIolani Community Science

Papayas are the only genetically modified (GM) crop that was created from start to finish here in Hawaiʻi. It was developed by USDA scientists in conjunction with local farmers back in the 1990s in order to protect an $11 million industry from the devastating impacts of papaya ringspot virus (PRSV). Unlike for most GM crops which are developed in the private sector, there were no restrictions on farmers freely propagating the GM seeds produced by existing GM papaya trees. As a result, on islands where PRSV is present, most commercially produced papaya is GM.

King Intermediate students sampling papaya trees in their school māla.

Papaya is also one of the most ubiquitous homegrown fruit trees across the islands, which in turn supports a substantial population of largely bird-dispersed feral trees. However, due in part to horizontal gene transfer during cross-pollination, an unknown proportion of these homegrown and feral papayas are now also GM.

So… is that papaya tree in your backyard or school garden GMO? How would you know? In this project, students bring in samples from their backyard papaya trees to be screened in class via a sequence of 2-3 lab exercises teaching DNA extraction, polymerase chain reaction (PCR) and gel electrophoresis. Students learn to detect unseen genetic modification with genetic tools while exploring the impacts of transgenic contamination in our cultivated landscapes within the context of food sovereignty.

GM Papaya Lab

Students supply papaya leaves from their yards for PCR screening of the CaMV1 transgene promoter in GM papaya.

LAB OVERVIEW

LEARNING OBJECTIVES:

Students will understand a generalized process for accessing information from DNA molecules
Explore foundational genetics lab techniques and equipment
Comprehend the mechanics, utility and impacts of GMOs

Crosscutting concepts: SI units, sexual reproduction in plants, organelles, cell division, chemical concentrations, electricity/electric charge

Lab techniques: DNA extraction, PCR, gel electrophoresis

Keywords: GMO, food safety, agriculture, environmental health