"A month - or, half a season - in either direction; I recall Nudge mentioned that our genes are made of quadruple helixes and not double?  They correspond seasonally, centered a year out from the conception date, and anything too far off from that isn't stable to attach the other three quarters of soul shapes to.  I just barely fit, myself, since I have September 01 and October 01 and October 40; one day farther apart and I don't think it would have worked.  Yet.  Nudge said it should be possible to engineer something broader; we might want to hire some winter solqs to work on that eventually."

"...is animal genetics like this?"

"I don't think so although as far as I know no one's looked at the sapient cats' yet!"

"Maybe I will have to do that! But first I wanna read a good history of the discovery of genetics - if it was discovered and not just, like, divinely revealed?"

"It was discovered."

"Got a recommendation or should I rummage around?"

"Do you speak Surran?"

"Not by that name, but also this isn't Latin as I knew it, so..."

Felicity produces a phrase incomprehensible to Cam.

"Not in my repertoire."

"Then I don't think I can recommend anything better than rummaging except by doing some of my own."

"I shall rummage, then!" With his cat in his lap and a cup of mocha.

In his rummaging, Cam first learns:

• Heredity has been known to be a thing for a long time, although it does seem to be somewhat less of one for humans than on his Earth, what with all the attractors for the various birthdays.
• Genetics specifically was discovered by living humans a century or two ago.
• DNA apparently stands for 'Difference Notation for being Alive', here.
• The basic building blocks for creating a member of a local species are all mostly the same and DNA just refers to the things that can vary between individuals.
• There are physically separate strands for species (SSNA, 'Species Similarities Notation for being Alive') and for being a living biological being at all (FNA, 'Fundamental' et cetera).
• Mules and ligers still exist.

Wow, that's weird as fuck. Do they have sex chromosomes? Trisomies? Mutations? What individual genes in which of the NAs are known to do what things?

Yes no depends on your definition.  There are genes for hair color and skin color and other things related to physical appearance, as well as the seasonal cruft Felicity mentioned, and then there's one for the birthday which forms when the soul attaches.

Do babies kick, in this universe? Do they have population variation in, oh, lactase persistence or alcohol tolerance?

Babies kick - and on further investigation soulless ones seem to have a little more capacity than basement dwellers, though only very little - adults do not as a phenomenon have trouble digesting lactose, and allergies as Cam knows them appear to not exist at all, although some forms of influenza are called that.  Alcohol tolerance varies mostly by birthday.

...wow. Anybody done anything in the gene therapy space?

Ugh, yes and it's awful.  Don't the people who do that know that they're defiling the subjects' fundamental nature??  Fucking winter solstices.

...were they doing anything actually sketchy or do people just hate the idea.

It's a mix; lots of perfectly innocuous things have real bad press and then there's stuff that's at least kind of wack like trying to make various supercreatures by messing around with SSNA and then - wow okay that's a lot of historical attempts to sapientize animals before cat uplift lady succeeded.

(Also it seems like there might be a chance that having one's 'nature' 'defiled' is worse for local lifeforms than naively expectable but it's kind of hard to tell around all the negativity.)

Has anyone with a defiled nature commented?

Some of them have commented negatively!  Some of them have commented positively but had weird symptoms, or died.  Some of them have commented positively and been, apparently, fine.

. . . In fact.  It seems like a fair number of autumn equinoxes totally do a ton of gene therapy and related treatments, mostly to themselves, in a way that gets basically no public press.  They have pretty extensive records which they share among their geminis, though.

...huh, cool? What are they doing?

Making themselves really hot, mostly.