Monday 26 March 2007

Conservation Conversations 2


GM Mosquitoes to KO Malaria?

Every 20 seconds, a child is said to die of Malaria in Africa. GM Anopheles mosquitoes were recently unveiled that had been changed to be resistant to the Plasmodium parasite by Mauro et al. (http://www.pnas.org/cgi/search?FIRSTINDEX=20&submit.y=8&submit.x=6&fulltext=GM+mosquitos) . Placing the altered mosquitoes in 'closed' environments with malaria-infected mice and wild type mosquitoes seemed to indicate that the GM version thrived. The study seems to be a more sophisticated extension of an earlier idea that involved releasing radiation-sterilised male mosquitoes to mate with the blood-sucking females. Supporting this development is the hope that the GM variety will replace the wild mosquito, reducing human to human transmission of the blood parasite (reducing human disease and deaths) without the need to resort (again) to environmentally-damaging insecticides such as DDT. The GM variety would still be available as a food item for insect-eating birds, fish and amphibia. Against this development are the observations that the 'closed' systems are highly simplified and that the GM variety would have to have a major advantage over the wild form to spread quickly and efficiently throughout the insect populations. Do they behave in the same way? Are they more or less prone to be predated? Some genes or combinations of genes do appear to spread quickly (e.g. it has be estimated that the genes that develop resistance to brood parasitism- generating so-called 'rejectors'- might well spread through an entire population in as little as 100 years. Things might well be faster in insects with their short life-cycles) but there is no real evidence as yet in this case for this . Other problems are that transmission of Plasmodium is not limited to the Anopheles mosquito in sub-Saharan Africa (there are a number of species involved). Some individual have expressed concern that the GM mosquitoes might become capable of transmitting some other agent such as HIV/Aids (although that seems rather unlikely).One might also add that, if the technique did work , one might have to reconsider the effects of extra over-population on the land, its flora and fauna

No comments:

A New Type of Money Laundering?

Thames Water is the UK's biggest privatised (thank you, Mrs Thatcher!) water company, with around 15 million customers. All such water...