[mikekchar]

There is a specific flavour (or flavours) in cilantro that can only be tasted by certain people. That ability is genetically linked. The flavour apparently tastes like soap. Similarly the ability to smell the really offensive odour of natto is also genetically linked.

However, I think it's a stretch to go from that (the ability to detect certain substances) to the idea that all tastes are genetically linked in a substantial way. For example the rate of ability to detect the soap flavour in cilantro is quite low (between 4-14 percent of the population based on random google searching) -- geographical variations in that ability might affect it's use in regional cuisine, but it's low enough that it might not. Most food doesn't have any similar obnoxious flavours, so I think you are correct that regional variation is more cultural than anything else. For example, the peoples of Korea and Japan are not really so different (and are even very, very close geographically), but Korean food tends to be incredibly spicy while Japanese food is decidedly not spicy.