yet to be discovered/identified/found
In Caucasians, mutations in a gene called CARD15 make a person susceptible to Crohn's disease, but Japanese with Crohn's disease have none of these mutations. Presumably a different gene, yet to be found, contributes to Crohn's in Japanese.
unidentified, undiscovered, unnamed
...provided validation that the unnamed feeling was an Autonomous Sensory Meridian Response ...
Edited in light of new information ("as in if you know something exists, but have not yet found the boundaries where it exists...don't know the chromosome or area...)
...restriction enzymes are used to cut the desired gene out of the DNA in which it is found.
The lower the number, the higher the chance that the desired gene will be expressed poorly.
.....cells, regulating the lengths of DNA fragments, finding a desired gene
...establish the function of the desired gene. ...the desired gene in a plastid... ...removed and replaced with the desired gene... ...enough offspring express the desired gene to make... ...the gene probe can only become attached to the desired gene.