Lois & Clark Forums Forums Fan Fiction Fanfic Related Home Ponderings: Genetics

I was pulled into LC fanfic by Nan Smith's Home series, and I remain an avid reader. I'm up way too late and really ought to be working on the things I'm up so late in order to work on; nonetheless, I started wondering about the odds of each power being passed on to the next generation. I don't know that anyone's hit this before, so here goes....

Referencing the annotated Kent Family Tree linked off the Archive, I find the following trends:

1) No one who does not have a given power will pass said power to their children. This means once a power drops out in a given line, it could only be restored by in-breeding. Since the family is big enough to have third cousins (the closest permitted by law...), we might see e.g. Meriel Olsen marry Matt Kent and have children with both powers. Maybe. Probably a little safer to marry off a different branch, and moreso once Clark and Lori's children get older -- only half-siblings to the others, they'd be a fresh gene supply.

2) Clark, the only full-blooded Kryptonian of the family, always breeds both powers true. 100% of his children carry both powers. Half-bloods still have good odds -- 75% of their children are super-powered and 75% telepathic. Obviously, this provides a good overlap. Only 1 in 16 children should be without either power. (In fact, there are only 11 children in the following generation, one of which has neither power.)

The third generation down is something of a blip, since it doesn't seem to lie smoothly on the curve for either power, but diverges in opposite directions for the two. Super-powers are more likely to be passed on in the third generation, while telepathy is less likely in the third than fourth. Probably due to insufficient sample size.

Nonetheless, in both powers, fourth-generation Kryptonians (1/8 Kryptonian) who have a given power have a 2/3rds chance of passing it on to their offspring.

3) As a general rule, it would appear that each generation is less likely to pass on a power that they have. There may be multiple genes that can pass on a power, any of which or a subset of which is sufficient to possess the power, but the number of which determines one's odds of propagating it. In this case, we would expect to see the odds of passing on a power decline rapidly (as we do) with each generation possessing fewer of the genes, then level out in future generations once almost everyone with the power has a single possible gene. If a subset, it is possible that non-powered children might see a power resurface through in-breeding.

It is also possible that the genes themselves are degrading via mutation with each generation, causing them to be less reliably transmitted. In that case, we would expect the powers themselves to be degraded -- perhaps not so noticeable in early generations when Superman is rarely pushed to the limit, but in this case we might expect e.g. Cyclone (Henry Olsen) at 1/16th Kryptonian to be noticeably less strong/fast/whatever than Superman. With the telepathic talent, this might manifest as a degradation of range -- and didn't Clark pick up the distress calls from the Christmas party before anyone else? That might not just be a manifestation of his link to Lori, but barely picking up telepathic signals that were imperceptible to anyone else.

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Nan, as I recall, you're a medical person -- have you got any of the genetic stuff in mind already? I'm just being nosy and curious here -- and if I'm completely off or interfering with future directions, I'll be happy to behave myself in your part of the playground. ;-)

Anyone with a better knowledge of genetics or stats than I care to comment on how this would actually play out?

Assume Kryptonian powers (both kinds) are dominant. Clark is homozygous dominant (two copies of the dominant gene); Lois is homozygous recessive (two copies of the recessive gene). Let's call him KK and her kk. (I will only look at one of the two traits. Clearly they are on separate chromosomes and assort independently.)

Offspring of a KK x kk cross would all be Kk -- heterozygous. They would show the trait, as all of Clark and Lois' kids do.

Offspring of a Kk x kk cross should be 50% Kk and 50% kk, statistically. However, those are the odds for each birth. Just as the odds of any given child being a girl is 50%, but some families have 5 girls and no boys, a Kryptonian trait might actual show up in more than (or less than) 50% of offspring of such crosses.

Moreover, I wonder if sperm/eggs that have a K might actually have better odds of fertilizing/being fertilized? This particularly makes sense for sperm, where speed counts.

Mendellian genetics

Actually, rivka has it pretty much right. Statistically, a super-powered (or telepathic) member of Clark's family has a 50/50 chance of transmitting the powers, and/or telepathy, however there are other factors that affect things, among them, plain old chance. Plus, of course, not all the family is represented in Artemis's geneology. As a rule, there is actually a bit of a bias toward the Kryptonian genes simply because they have a slight edge over the Earth ones.

Nan

Okay -- I was discounting the simple single-allele model since there was the declining rate of passing it on. So are we just seeing an advantage to K-blessed sperm? How would a theory like that account for a mother's predilection to pass it along? Though I didn't break it down by parent gender, so....

I'm curious, though.... Does that mean that LL&CK did have other grandkids who were perfectly normal, already died, and don't appear on the list? Seems like Clark would have mentioned it if there were three or four deceased grand-kids in his past.... Anyway.

That might be true, but they weren't germaine to the story. I'm really pleased you like the Home series to the point that you're interested in all the details , but I'm going to have to leave parts of it to people's imaginations However, the grandkids are in their sixties at this point, so it's quite possible that they're all still alive, given the advanced medicine of the day. There are, as you will notice if you check the geneology, only four grandkids listed who are either telepathic/non super powered, or simply normal, so there would be a good chance that they were all still alive.

Nan

Being a biology teacher pays off on occasion.

I just list what Nan tells me . She has a pretty firm idea of what is going on. The reason I started diagramming the Kent Family Tree was I was lost on who related to whom in the stories. I tend to like graphics. Rivka's explanation made sense to me, but I'm a physicist not a biologist.



One of the things I'm intrigued about is that she has placeholders like "3 kids" unnamed. I think this series will go on a long time (yay)!

Artemis

I do this with my sweetheart, too -- she's an aspring author, her current passion is a fantasy novel, and I drive her crazy poking and prodding at the mechanics of her characters' powers. The price she pays for hooking up with an engineer!

Not trying to interfere with anyone's imagination, just trying to figure things out....

Lol! I completely understand. I'm married to an engineer, too!

Nan