We can and do go from phenotype -> genetic code as long as the phenotypic ask is something we have some familiarity with. There are enough examples out there t

We can and do go from phenotype -> genetic code as long as the phenotypic ask is something we have some familiarity with. There are enough examples out there that even though the toolbox is still small, there's plenty of new things we can rationally design - even if our success rate is not 100%. Transcription Factor + GFP -> green transcription factor -> codon-optimized plasmid Membrane tag + light-activated conformational change + cytoskeleton -> optogenetic mechanotransduction Small-molecule-activated degradation domain + transcription factor -> chemically-induced genetic switch. And though there's still a bit of trial and error to debug which/how those components go together, it's a common enough thing to be reasonably accessible.