First, let's clarify the terminology. In RimWorld Biotech , a is a genetic modification of a baseline human. Unlike an Endogene (genes you are born with that cannot change), a Xenotype consists of Germline genes —inherited traits that can be passed to offspring, but can also be altered via the gene assembler.
By default, custom xenotypes only appear if you start with them. To see them in the wild, players often use mods: rimworld create xenotype
To create a xenotype mid-game, you must research and build specific infrastructure. First, let's clarify the terminology