Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Saturday, January 16, 2016

The Fear of Unforeseen Consequences

"[Gene drives] could potentially prevent the spread of disease, support agriculture by reversing pesticide and herbicide resistance in insects and weeds, and control damaging invasive species."
2014 eLIFE journal, scientific group

"[. . . a single escaped organism with a gene drive system] could alter a substantial fraction of the wild population with unpredictable ecological consequences . . . [thus] the decision to deploy a gene drive must be made collectively by society."
scientific group: Nature Biotechnology, November 2015

"Clearly, the technology described here is not to be used lightly."
"Given the suffering caused by some species, neither is it obviously one to be ignored."
Austin Burt, biologist, 2003 theory of gene drives
Kudzu Covered House
This abandoned cabin is tucked back in the woods and even though it is visible from the highway it is hardly noticeable. There are many such houses which lie in the path of the ever spreading kudzu vine

The scientific minds with which society is blessed are minds consumed by curiosity, always on the search to discover new ways of looking at nature, of taming nature, of advancing the fortunes of humankind. Sometimes they theorize and then strive to conduct research that will fundamentally inform them that their theories are correct, giving them the 'authorization' through validation, to proceed with their theories on the basis that they believe they will make the world a better place.

picture of zebra mussels
Picture of zebra mussels, Dreissena polymorpha, that invade and starve local populations, Lake St. Clair, Michigan, USA

Sometimes their long-range views are validated by the outcomes, the results of their applications to problems that needed to be addressed. And sometimes, what has happened when science decided it had the right answers to the problems that seemed intractable but they felt would be amenable to a solution of their devising, they inadvertently unleashed disaster; an outcome that they hadn't foreseen but which, when it happened, made the original problem they were addressing less urgent than finding a solution to the solution gone awry.

We see that kind of thing in a way when people have been diagnosed with bodily functions that have gone awry and which require pharmaceutical intervention to help the body balance itself. And then a drug is prescribed, and while it does address the problem more or less, it also manages to create other problems through pharmaceutical side-effects. No solutions turn out to be perfect, complications arise where they are perhaps least expected. Or they are anticipated but it is felt that they are minor in comparison to the condition they're addressing.

Scientists working with the technique of a gene drive system propelling genes toward a certain targeted outcome feel they may finally have the solution to one of the world's foremost pestilences; mosquitoes which carry viral agents and pathogens inimical to peoples' health and longevity. In laboratory experiments scientists have succeeded in transforming the ordinary fruit fly through gene drives to convert an entire colony to carry a gene favoured toward a certain end.

Sinclair Stammers/Science Photo Library
The Anopheles stephensi mosquito can spread the malaria parasite to humans.

It has been established by science that such mechanisms can work with organisms that have a very short lifespan; it would take infinitely longer, perhaps forever in human time-terms to use that kind of manipulative protocol on large mammals, for example. An application of gene drives is foreseen as a vital potential aid in ridding the world of diseases borne by ubiquitous pests carrying malaria, dengue fever and Lyme disease, for example.

Such a mechanism whose purpose is to alter a population to the point of extinction is known as a crash drive. For example a gene engineered targeting mosquitoes to ensure that all offspring are male; the number of females declining with each generation until the population is no longer viable. Alternately, to endow mosquitoes with genes making them malaria-parasite-resistant. This has already been undertaken as a test project by scientists in California.

Such success at initial stages must appear promising, but on the other hand, no gene drive organisms have yet been released outside of a laboratory as an experiment, and so biologists are unable to assess how well they work work in nature. More to the point, perhaps what risks may arise. There are ample instances where well-meaning biologists and botanists have introduced alien species to an natural environment which have no natural 'enemies', in hopes of establishing them for a sound purpose, only to find them overwhelming local species and upsetting the balance of nature.

Within two generations 97 percent of fruit flies used in an experimental laboratory by two biologists at the University of California, were successful in installing a gene drive system carrying the genetic trait for albinism. A success in demonstrating the potential of the method; at least in the laboratory. But as a result urgent calls from other scientists emerged, cautioning that should a fruit fly  with a gene drive escape, it could affect its species worldwide.

It cannot be completely understood theoretically how ecologically destabilizing it might be to introduce a gene drive into the natural world at large. Should mosquitoes be eliminated, how would that affect nature's pendulum? Unintended consequences loom darkly on the horizon; once a natural pattern of existence has been irreversibly altered, how to ameliorate a lopsided result threatening other areas of nature?

picture of adult cane toad
Invasive cane toads might one day be controlled with CRISPR gene drives. Photo Credit: U.S. Geological Survey

In the realm of the unexpected there could be the issue of target species responding to the interference in their genetic code by somehow managing to subvert the purpose of the gene drive to result in greater issues of pathogens; possibly even contaminating the issue by spreading the pathogens they are known for to other species? One thing is certain, science sits on no opportunity without making its move one way or another.

Displaying thumbnail of video Gene Drive-HD.mp4

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