As mentioned in the announcement, all not-cats have a new gene segment at the end of their genetic sequence that doesn't affect them, but will affect crossbreeds between not-cats and future species. It's been randomly assigned for currently-existing cats. What I'm curious about is, what does this segment look like for your cats that have had a family tree used on them? I have three, and they are:
[RB]
[BR]
[RB]
Are there other letters?

I looked at the two cats I used a family tree on, and their letters are:
[YB] - Finch
[LB] - Panda

My gene-revealed cats have a combination of B, L, R, and Y.

[ RL ]
[ YR ]
[ LL ]
[ BL ]
[ LB ]

BL

BB

LY

Some other combinations I've seen on my cats are BY & LR,
so it seems like the letters in it are B, Y, L, R ? There might be other letters but those are the only ones I've seen on my family tree'd cats

ive revealed too many of my cats genes to bother linking them all so heres the list of the new gene bit with my cats, not really sure what they could mean so far but i hope my large sample size helps ya guys lol

shou: bl - etburn: bb - polo: bl - opal: bb - toshi: lb - vigoth: ll - laracal: bl - hoax: lr - clause: yr -
telpur: rb - yuna: br

The two cats I have Family Tree'd are [YL] and [YB]. If it's for new species, then I'm guessing it could influence Mer-cat tail colours. Y= Yellow, L= Lavender, B= Blue, R= Red .

Thank you all! I've looked at some sequenced cats from other accounts myself and it seems there's just the four letters, or maybe there's a super rare fifth one Mercat tail color does seem to be the most likely use of these, since we know those are coming sooner than other not-not-cat species.
R and Y are probably Red and Yellow, but I don't know about the mysterious L Personally, I'm guessing it's either Blue or Black, and B is the one that it isn't? It might also stand for Light, and LL mercats would have white tails, LX kitties a pastel color? Ehhh... Kind of unlikely, though, it'd probably be W in that case.