So, two quick points in response: 1. Yeah, I probably overstated the case. It's not as if it's impossible to move a gene somewhere else on a chromosome and hav

So, two quick points in response: 1. Yeah, I probably overstated the case. It's not as if it's impossible to move a gene somewhere else on a chromosome and have it function completely normally. As you point out, we do this all the time. That said... 2. Genetics is hard, and I'm of the school of thought that one reason it is so hard is because systems are more fragile in meaningful ways than we assume. That is to say, if you attempt a gene translocation 100 times and get 3 successes, most geneticists would be happy with that result and not question the 97 failures. And, indeed, it is entirely possible that the quality of the reagents, the stringency of the protocols, or any of an infinite number of other variables that have little or nothing to do with genetics could be the cause of those 97 failures...or, it could be that 97 times the translocation worked but the product wasn't viable. I know from experience that it is very hard to distinguish between these possibilities, and furthermore that in the publish-or-perish world of academia today there's not any motivation for navel gazing into the reason most genetic protocols are not more efficient. That said, I've seen hints in my past work that make me think location, gene dose, DNA secondary and tertiary structure, etc. are more consequential than the common wisdom would have you believe. (Oh, and for anyone still reading, I'll share the brain teaser that was my light-bulb moment for the extent of gene dose effect in prokarya: it takes 40 min to replicate the E. coli genome, but during exponential growth E. coli can double in number every 20 min. How?)