Jdt in the comments brings up some issues with genetic weapons that I’d like to address because they contain common misperceptions:
1) A bioweapon targeted at a specific ethnic group wouldn’t necessarily require “gene variants that are ONLY present in particular ethnic groups”.
Yes it would. Otherwise you’re just as likely to slaughter your own people
1b) We would expect a great deal of intergroup variation in genes related to immune function, since past epidemics will have had strong selective effects and different groups have different disease histories.
Wrong. Humanity’s immune system is pretty much the same. What differs is what diseases a group has been exposed to, hence the disproportional effects of smallpox on an immunologically naive population like pre-Columbian Amerindians. The Spaniards weren’t immune to smallpox primarily because of their genetics, rather it was due to prior exposure to either smallpox or cowpox (Amerindians didn’t have cows either). Most of the variations you can attribute to “strong selective effects” have mainly to do with some blood-type distributions.
1c)it doesn’t seem at all far-fetched to me that someone could develop a weapon that affects, say, 50% of the enemy and 5% of their own people.
That may be possible. But why bother when you can develop a nuke for far less (the technology already exists) that will kill 100% of the enemy (if used “liberally” enough) and none of your own population (assuming massive first-strike advantage). Oh yeah, that nuclear winter scenario. so what? If they’re (enemy dictators for the most part) willing to kill 5% (or likely, more) of their own population, why would they care about a hypothetical nuclear winter?
2) The obvious example is the effect exposure to European diseases had on Amerindian population of North America. There was no doubt a great deal of genetic variation within the population of Amerindians, but what they had in common was not having been exposed to European diseases.
Again, not a genetic effect. This is what happens when an immunologically naive group is exposed to a very special virus (smallpox).
What you’re talking about is essentially introducing another disease like small pox to an immunologically naive population (all of humanity). With one crucial exception–that the virus is targeted to SPECIFIC genes present in one ethnic group versus another. Not only that, but these genes need to be present in a good number (20%? 50%? 100%?) of the target population. These genes that cause differences between Pygmies and Eskimos may exist, but between Arabs and Jews? Doubtful.
3) For example, the CCR5-32 allele that confers some protection against AIDS
This gene is found in around 20% of the European population to my recollection.
I suppose this could meet your criteria for a gene-based weapon. Although carpet bombing seems a much cheaper and more reliable weapon.
4)The question of whether or not it’s possible is totally seperate from the question of whether or not the Israelis are working on it. Do you have any reason to believe they’re not?
Well, considering it’s widely known that Israel has nuclear weapons, despite denials or prevarications by the government, I doubt they could keep the massive program required to carry out this program secret. But that’s the beauty of conspiracy theories…they’re incapable of being disproved