GM Mosquitoes Block Malaria Parasites in Tanzania Study
Why in the news
Researchers in Tanzania have shown that engineered mosquitoes stop wild malaria parasites in blood from infected local children.
Key facts
- Partners: Ifakara Health Institute, National Institute for Medical Research (Tanzania) and Imperial College London.
- Mosquito: Anopheles gambiae carrying magainins (frogs) and melittin (honeybees).
- Test: mosquitoes fed blood from infected Tanzanian children destroyed parasites in the midgut before maturity.
- Milestone: first such strain developed in Africa by African scientists.
- Gene drive: CRISPR-Cas9 copies a trait to the partner chromosome, giving over 90% inheritance.
| Strategy | Mechanism | Aim |
|---|---|---|
| Population modification (replacement) | Genes trigger anti-parasite molecules when the mosquito bites | Keep mosquitoes alive but unable to pass malaria on |
| Population suppression | Targets the doublesex gene so female offspring are sterile | Shrink or collapse the local population |
Key concepts
- Why needed: insecticide resistance is growing and mosquitoes now bite outdoors by day, dodging bed nets.
- Split gene drive: a safety design keeping the scissors and template in two separate lines, so they act only when combined; this allows controlled testing.
- Safety debate: modification is seen as safer than suppression since the mosquito stays in the food chain as prey for birds and bats.
Exam angle
- Tool: CRISPR-Cas9 used for gene drive.
- Target insect: Anopheles gambiae; disease: malaria.
- Gene named for suppression: doublesex.