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Comment by jimworm | Hacker News Reader

I've recently been thinking about the possibility of a genetic disease for mosquitoes, transmitted down male lines but killing only females of the same brood, with the intended result that a relatively small release of males can cause an extreme imbalance in the sex ratio and possibly the elimination of mosquitoes from an area.

The different mechanisms of mosquito sex determination aside, I haven't been able to work out something that might be feasible. Wondering if anybody else had similar ruminations, and if you'd share some of your thoughts?

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Once you start to get a sex imbalance then the genetics of future generations as a whole will disproportionately be determined by the female population, which won't have any copies of the gene. Eventually the gene will be eliminated from the population. It's the same principle that causes most species to produce equal number of males and females despite that not being ideal for the species as a whole.

This has basically already been done using a bacteria called Wolbachia [0].

[0] http://www.eliminatedengue.com/our-research/wolbachia

Thanks to your cue, I found a candidate gene that might fit the bill called Medea [0]. Wolbachia itself won't cause catastrophic sex-ratio imbalances, so does not cause a "White Plague" scenario.

[0] http://www.nature.com/scitable/blog/bio2.0/engineering_in_th...

Similar to a segregation-distorter. This occurs in some mice. The gene causes copies of itself to be present in all it's children by making them all one sex (male). The gene is highly selected for because it makes twice as many copies every generation than the alternative gene. And there is otherwise no difference between a male carrying the gene and one not carrying it.

If you released a gene like that on a species, soon there would be no females left and they would all die out.

This would only work for a while, and then, "nature would find a way".

Sometimes I think no one even bothered paying attention to Jurassic Park.

Nature does not always find a way, look at the fossil record for evidence.

Birds are still around. Nature found a way in that specific case.

When you look at the successes of nature you cannot help but marvel at it's ingenuity. But then you look at it's failures and you can only marvel at it's stupidity.

Nature is just like a password cracker tries all possible combinations of characters. Most tries are wrong and the clock is always ticking.

Nature will find a way if it has enough room for trial and error. Say, millions of germs mutating inside millions of hosts using antibiotics, trillions of mutations trying to beat a single molecule. By the time the Cretaceous environment recovered, birdosaurs could not regain their place on the top of the food chain because that space was taken over by mammals.

So if the extinction is swift and massive enough, the ecosystem will shift and there will not be a way to be found. So you should always ask: what dreadful bloodsucking beasts will replace the mosquito ?

I would much rather prefer they breed a transgenic mosquito unable to spread dengue than try to wipe all mosquitoes off the face of the planet.

Humans have been very successful at beating evolution, if more by accident than purposeful action. Mosquitoes won't be pushovers like the dodo were, but if we eradicate one species of them they won't be the first insects we've driven extinct on purpose.

Not necessarily. Evolution isn't magic and lots of species go extinct. And evolution has never been optimizing for the survival of the species. It selects for individual fitness and sometimes even the fitness of individual genes.

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