DNA return #1: Genetic Drift

[Tdarcos]

In this article, Rae spoke about how she'd discovered that DNA only has a half-life of 521 years. She kind of wondered, based on the idea ("Xenos paradox") that to get to anywhere requirea a travel of 1/2 the remaining distance, which means you always have 1/2 of the remaining distance left, i.e. you cn't ever get there. Now, I'll tackle that one later, but for this one, I'd like to look at another DNA issue, genetic drift.

We talk about "evolution," that subject that gets fundamentalist Cgristians into a lather, and most of the rest of us neither understand nor care. Bur what is evolution?

The technical will say, "change in frequency of alleles in a population over time" where 'alleles" are "one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome." Genetic drift, that is. Evolution happens when conditions in the environment require an organism to change to adapt to it. Where conditions that are unfavorable to life occur, life that is not suited to the new conditions dies. Those whose genetic make up are compatible live and breed, and their descendants are the survivors. This is what is meant by "survival of the fittest." It does not mean the smartest or the strongest, it means the ones whose genetic make up survived in the existing environment long enough to breed.

If you have ever had to kill an infestation of fleas or roaches from an apartment, you have probably noticed that you have to keep changing the insecticide to a new formula every so often, because the bugs become immune to the insecticide you were using.This is a clear example of evolution: the bugs that had the gene that is immune to that particular insecticide survived; the other ones died out. That means that the new crop of insects which now have the gene that makes them immune to that older one, now breed in the environment.

That's why you have to keep changing the insecticide to compensate for insect evolution.

[Tdarcos]

Now that I discussed the idea of evolution, genetic changes over time. Now here's another point to be made and that is that as those changes diverge more and more from the original organisn, the species of the new one will change.

We don't know exactly when - at which point - because species is not a hard, drop dead line. As long as two entities can breed with each other, they are of the same species This means we get "transitional" species, one that can breed with each other and with close generation later ones, but the later ones can't breed with the prior ones

To make this simpler, let's take species"A" which breeds, and it's descendants breed, and eventually the new breeds develop into something different, B. A and B can breed with each other. Eventually B evolves into species C. C is somewhat different from B, but they can still breed with them. They might or might not be able to breed with A. Eventually C evolves to become D. But, as with the others,, D can breed with C and D. But it can'tt breed with A or B. While A and D are clearly separate species, are B or C?

This has been seen out in the wild. There is a place where a South river split into two tributaries, East and West. A species of fish grew native to the south river continued up to the tributaries, some going eouth, others going west, then becoming trapped and unable to go back downstream. Fish on each side of the river adapt to changes in the river ecosystem, These species each developed differently from each other. South river fish swam into either branch, could breed with either, but the East fish can only breed with South and East, and West fish can only breed with South and West.

At some point the river merged into the North river. Ñow you have one species and two transitional ones: South, East, and West. As conditions change, some or all of these may go extinct, but for those that survive, if conditions are differen enough, yet another species. Or perhaps more.

[Tdarcos]

Now I get to people. Every child born is a mutation of it's parents, because like shuffling cards from two different decks, they get half of their chromosomes from their father and half from their mother. I don't know enough, and am too lazy to check right now, to speculate on whether each chromosome is from only one parent or if the offspring can get parts of one chromosome from each.

Having stopped to check, as best I understand the references, the cromosomes are each from.one or the other parent. They di not "split the baby in hald" to mix metaphors.
So the playing card analogy is fairly good; all you get is one card from each deck, not bits and pieces from either.

Since genetic drift occurs with every single offspring, and every child is a mutation of it's parents, it stands to reason that our descendants will eventually be different from us. Consider that our species, homo sapiens, is only 300,000 years old. Life had bern.here for hundreds of millions of years before the various mutations of lesser soecies came together to make us

If conditions are good for humans, we might not mutate radically; the shark is such an apex predictor that it is pretty much the same as it's ancestors of 5 million years ago Or we might become radically different. Maybe better resistance to toxic chemicals. Better ability to sut at a desk for hoursbdauly or better back support for standing all day. Maybe prevalence of vaccines make us less resistant to duseases. Or there may be changes so radical that we might be hard pressed to recognize what we evolve into.

So, it is possible, since man manipulates his environment to make it habitable for us - or we have for about the last 20,00/ years - that we might not change much in another 300,000 - 1,000,000 years. Or we may change so radically that the world's #1 apex preditot transfilorms into an entirely different species.

[Tdarcos]

If we do change enough to become a different species, at best it will be a minor news article in segment 75 of the optolythic news, transmitted from planet to planet. Unless we change so much that (1) separate branches of homo sapens exist; (2) that environment has challenges requiring adaptation; (3) they evolve to survive in that environment; (4) they breed; (5) the changes are so radical they can't breed with us, we may never even notice. Each transitional species had a fun time practicing, then eventually breeding, to produce the next generation. Some transitionss will die out because the combinations produce lethal results resulting in miscarriage, or undesirable resuts that produce babies and children with deformities that make it impoosible to survive long enough to breed.

Since the intermediate species' humanity evolces throgh, can breed with each other, all that happens is parents might notice ancestors were radically different 0 if they notice - but all they see is the lovely baby boy or girl they produced. (Don't give me crap about non-binary genders; for homo sapiens, reproductive biology dictates either you pirch or catch. Either you "pitch" and produce gametes, or you "catch" and you provide eggs and a womb.) Some mutations may be obvious: green eted mother and brown eted father produce a recessive child with blue eyes. (This is not prejorative: some genes have a higher probability, or are "dominant," and others have less, so they are "recessive," If either parent's genes had "voted "for green or brown, it would have gotten that color. Both had to "vote" for blue to get blue eyes. (If they both voted, either one is the higher dominant, or the kid ends up with two different eye colors.

[Paul Robinson]

Wrong.

[Not-so-casual Observer]

If we do change enough to become a different species, at best it will be a minor news article in segment 75 of the optolythic news, transmitted from planet to planet. Unless we change so much that (1) separate branches of homo sapens exist; (2) that environment has challenges requiring adaptation; (3) they evolve to survive in that environment; (4) they breed; (5) the changes are so radical they can't breed with us, we may never even notice. Each transitional species had a fun time practicing, then eventually breeding, to produce the next generation. Some transitionss will die out because the combinations produce lethal results resulting in miscarriage, or undesirable resuts that produce babies and children with deformities that make it impoosible to survive long enough to breed.

Since the intermediate species' humanity evolces throgh, can breed with each other, all that happens is parents might notice ancestors were radically different 0 if they notice - but all they see is the lovely baby boy or girl they produced. (Don't give me crap about non-binary genders; for homo sapiens, reproductive biology dictates either you pirch or catch. Either you "pitch" and produce gametes, or you "catch" and you provide eggs and a womb.) Some mutations may be obvious: green eted mother and brown eted father produce a recessive child with blue eyes. (This is not prejorative: some genes have a higher probability, or are "dominant," and others have less, so they are "recessive," If either parent's genes had "voted "for green or brown, it would have gotten that color. Both had to "vote" for blue to get blue eyes. (If they both voted, either one is the higher dominant, or the kid ends up with two different eye colors.

My dad was brown eyed,
and my mom was blue.
I got my mom's blue eyes, until...
Well, they say that a severely traumatic
event has to happen for someone's eyes
to go from blue to grey...

And it turns out that I cried the blue
right out of my eyes!

I have photographic evidence.

[Tdarcos]

Well, they say that a severely traumatic
event has to happen for someone's eyes
to go from blue to grey...

And it turns out that I cried the blue
right out of my eyes!

And now I know why you have the nickname of "Blue," Raechel.

All DMA is, is the 'blueprints' of an organism, they have no bearing on what can happen after birth. Now, unless you weren dropping LSD or involved in other activities that cause chromosome damage before you had them, whatever children you had if this incident occurred befor that, your genes would still have 'voted' for blue eyes. If your partner had a more dominant gene, the offspring wull get whatever eye color they 'picked.' Blue is a weak, or recessive gene, brown or green are 'dominant' genes.

I'm not even going to guess and I'll accept that your etecolor changed. Trumatic incidents can cause physiologival changes that might otherwise be unbelievable. There is a story of a woman who was in the carage where her son was working on a car when it fell on him. Unassisted, she lifted the multi-thousand-pound vehicle up enough for him to get out. I think she spraigned a few things, but absent the traumatic incentive she could not lift the car when trying again later.

[pinback]

That's an urban legend.

[AArdvark]

you have ever had to kill an infestation of fleas or roaches from an apartment, you have probably noticed that you have to keep changing the insecticide to a new formula every so often, because the bugs become immune to the insecticide you were using

Commander, have you had personal experience with this?

[Not-so-casual Observer]

Just Google it.

"Can trauma cause blue eyes to turn grey?"

I already know the answer bc my doctor told me.

[Tdarcos]

you have ever had to kill an infestation of fleas or roaches from an apartment, you have probably noticed that you have to keep changing the insecticide to a new formula every so often, because the bugs become immune to the insecticide you were using

Commander, have you had personal experience with this?

In our apartment in Long Beach CA for both; the fleas you could only use a particular brand for one treatment. Must be done three times, not sure if it was weekly or every two weeks, but it works like this/ First blast kills all live fleas but not eggs. Second kills fleas that hatched after first treatment. Third kills any fleas that hatched from them. The place should now be clean.

By the time I got on the East Coast I knew about boric acid and it was only roaches. That is a biologicak poison, not a chemical one. They can't become immune. Twice I've cleared whole houses from a single application of boric acid. It is good stuff. No, it's actually great stuff. And food grade ditomaceous earth is almost as good while being safer for plants and pets.

[Ice Cream Jonsey]

I skimmed a bit and will re-read tomorrow but if you throw boric acid at people, sure, colors can change.

[Not-so-casual Observer]

I skimmed a bit and will re-read tomorrow but if you throw boric acid at people, sure, colors can change.

Lmao