PARIS, Oct 2: Scientists announced on Wednesday they had unravelled the genetic map of the mosquito and the malaria parasite, creating a weapon that may have the potential to eradicate one of humanity’s greatest scourges.

Their six-year effort may one day yield dazzling new drugs, smart repellents and vaccines that, it is hoped, will not only stop malaria in its tracks but also attack other fatal mosquito-borne diseases.

Malaria is a plague in dozens of poor tropical countries, reaping an annual harvest of more than a million lives and leaving hundreds of millions sick,the overwhelming majority of them infants in sub-Saharan Africa.

The scientists set their sights on squencing the DNA makeup of the blood-sucking mosquito Anopheles gambiae, which transmits the microscopic parasite to humans via its saliva, and of the most lethal parasite, Plasmodium falciparum.

“The genomes of these two organisms, along with that of the human, provide a triad of critical genetic information relevant to all stages of the malaria transmission cycle,” an editorial declared in the US weekly Science, which publishes the research in next Friday’s issue.

“They offer unprecedented opportunities to the scientific and public health communities engaged in the fight against malaria, a disease that exerts a huge toll on humanity.”

Doctors say genomics, the study of the inherited code, throws up the most exciting tool to combat disease since the advent of antibiotics more than 60 years ago.

A genome comprises the map of the DNA coils, or chromosomes, which provide the chemical recipe for making and sustaining an organism — the creature’s “book of life,” holding the secrets to all its strengths and weaknesses.

The mosquito genome, whose code has been sequenced by a team led by Robert Holt of the US biotech giant Celera Genomics Inc., is about twice that of a distant relative, Drosophila melanogaster, a fruitfly that is the basis for biotech research on insects.

For some intriguing reason, though, both insects, have about the same estimated number of genes, the protein-making machines that stud the chromosome: 13,683 for Anopheles, spread over six chromosomes, and 13,472 for Drosophila.

P. falciparum, whose sequence is published in Thursday’s issue of the British weekly Nature, comprises 14 chromosomes that encode about 5,300 genes, according to a team led by Malcolm Gardner of The Institute for Genomic Research, a not-for-profit research organisation located like Celera in Rockville, Maryland.

Having a map is not the same as understanding it or using it properly, and the researchers stressed that a long road lies ahead, especially in figuring out what the genes do, before new antimalarial weapons come on stream.

But there is already progress.

Holt’s team said they believed they had already spotted genes that could help make the mosquito immune to some insecticides.

And another group, led by Laurence Zwiebel of Vanderbilt University, Nashville, Tennessee, said they had identified genes that work Anopheles’ odorant receptors — astonishingly powerful sensors that can sniff prey from kilometres away, thanks to fatty acids found on human skin.

“If we can identify the receptors that mosquitoes use to smell humans, we should be able to design novel repellants and attractants that can substantially reduce the incidence of malaria, West Nile encephalitis, dengue and yellow fevers and other mosquito-borne diseases,” said Zwiebel in Science.

Other rich paths to follow will be understanding how the parasite is able to evade the human immune system; exactly how it lives and mutates in the mosquito’s gut and salivary glands; and why it has become resistant to chloroquine, the cheap, easy and safe front-line medication for which there is no comparable substitute.

One controversy-in-waiting is whether genetically-modified mosquitoes — engineered for instance so that they cannot hand on the parasite — should be released into the wild, where they would mate with their counterparts and eventually create a strain that is malaria-free.

But that is a question fraught with environmental fears, nor is there any guarantee that it would work.

And despite the genome breakthrough, budgets for malarial research and control — currently 300 million dollars a year from all sources — are still disastrously ort of what is needed to tame the disease.

“This is a mere fraction of the sums made available for bioterrorism research in the wake of last year’s anthrax attacks” in the United States, Nature pointed out.

Despite this, the two genomes have been placed in the public domain, which should spur research. The endeavour was a public-private partnership that mustered scientists, grants and private funds from a dozen countries, including the United States, Britain, France, Germany, Russia, Greece, China and Israel.—AFP