Hi.
If you do CRISPR to make a mutation that is exactly same as already reported mutation, do you make new allele name?
I’m making a same mutation in the different genetic background.
Thanks!
Best,
Dongyeop
Yes, every “instance” of a mutation should get its own allele designation. This includes re-creating the same mutation in a new background, and also independent isolates of a mutation (if you get more than one) from the same genome engineering project. The reason for this is that you may think two mutations are identical, but you don’t really know - even if you sequence carefully, there might be second-site mutations that you don’t detect. Every isolate of a particular mutation should be named and tracked independently in case you discover problems with one of them later.
Thank you so much!
I agree with everything said here, and at the risk of hijacking this old thread because of several recent frustrations, this is what I believe about allele numbers and strain numbers. Please argue with me if you disagree, and
perhaps similar clarification could be added to the nomenclature pages, because I think this is often poorly understood 
-every time you knock in a mutation for a co-conversion marker w/ CRISPR, it is a new allele. Even if to the best of your knowledge it is genetically identical to all of the others created before,
there might be a collateral mutation. The allele number is in essence the unique identifier assigned to that mutation as well as its origin.
-if you use CRISPR to build a double mutant rather than building a double mutant chromosome, you should give the newly generated allele new allele number.
-if you outcross a mutant or if you rebuild a strain that broke down, the new strain should have a new strain number, even if its expected genotype is exactly the same as that of a preexisting strain.