Genetic Superiority

[JoeEllison]

Really, you all didn't need to bite your knuckle in aprehension, I'm not trying to be cute, and I'm not 'teetering' on the fence of racial superiority from genetics. I'm not Comte Gobineau.

All it took was a "Chris, my boy, your observations and assumptions are wrong: dark eyes, hair, and skin aren't automatically dominant over fair features."

But thanks for all the info.

Actually, the suggestion that you watch your phrasing in general was probably more valuable advice in the long run.

 

[Cuddles]

Really, you all didn't need to bite your knuckle in aprehension, I'm not trying to be cute, and I'm not 'teetering' on the fence of racial superiority from genetics. I'm not Comte Gobineau.

All it took was a "Chris, my boy, your observations and assumptions are wrong: dark eyes, hair, and skin aren't automatically dominant over fair features."

Which was said in posts 5 and 7 at least. You appeared to ignore those and carried on asking. Most people don't find deliberate ignorance "cute".

 

[chris epic]

Which was said in posts 5 and 7 at least. You appeared to ignore those and carried on asking. Most people don't find deliberate ignorance "cute".

Sorry I didn't respond to your responses, but I'm sure you can get along without my affirmation.

Did you notice I thanked everyone for the information in my last post???


So I get it now, its a chance thing. But I'm still curious why the chances that dark features will be dominant over lighter features are greater than the later (from my observations). That's something that you didn't explain so that's why I'm still asking.

The spectrum of my observation runs on my encounter with ethnically-mixed offspring throughout my life. And I've payed closer attention recently with filipino/caucasian mixes because I myself will be having children like that.

Ultimately I guess, what are the "chances" I'll have a child with blue eyes who's mother is Asian?

 

[chris epic]

This article on variation in human skin colour .

I appreciate that link, thank you.

 

[Alric]

Ultimately I guess, what are the "chances" I'll have a child with blue eyes who's mother is Asian?

If she has brown eyes it depends on whether she carries a recessive alele for light eye color. If she carries a recessive its 50% chance. If she doesn't its 25% chance.

 

[chris epic]

I'm not sure "how much" but there is a very good possiblity she has European from the Spanish Colonial days. Both her mother and her father have Spanish-root surnames- so I bet that alelle is floating around in there somewhere.

Thanks

 

[Lucky]

All it took was a "Chris, my boy, your observations and assumptions are wrong: dark eyes, hair, and skin aren't automatically dominant over fair features."

But thanks for all the info.

So I get it now, its a chance thing. But I'm still curious why the chances that dark features will be dominant over lighter features are greater than the later (from my observations). That's something that you didn't explain so that's why I'm still asking.

I'm not sure you do "get it" yet. You still seem not to have grasped the point that dominant/recessive properties of the gene act at a molecular level, and are (to a good approximation) fixed, whilst selective advantage is a function of the environment and therefore variable. We can assume that if allele A is dominant over a in one individual, it is in everyone. Common dominance mechanisms (where A codes for an enzyme) include a not coding for anything, or coding for a completely ineffective molecule, or for a less efficient enzyme.

Now, there is plainly some reason to suppose that A might be more useful to the body than a, assuming the kind of dominance mechanism above - for example, if the enzyme is involved in a biochemical process essential for life then a could be a lethal or highly damaging recessive. Perhaps this point is partly responsible for the confusion. But it is not a general rule – because not all dominant/recessive mechanisms work like this, and because the body might be better off without the enzyme, or with less of it, or a different form.

Human skin colour doesn't follow the 'rule' at all, because there is no optimal skin colour – it's highly dependent on environment. It's interesting that the selection pressures against being too fair in a sunny climate and being too dark in a less sunny one are of comparable strength. Given that fact (and this is where "chance" comes in, not in the dominant/recessive mechanism), we can expect some general properties of the genetic system affecting skin colour:

• A number of genes are involved, interacting in a complicated way.
• Where identified, these genes tend not to have a simple, predictable effect, constant across all populations.
• We don't see any simple Mendelian inheritance pattern in skin colour.
• For parents with very different skin colours, the children tend not to resemble either very closely.
• Humans have the ability to alter their skin colour directly in response to the environment.

All of these are borne out by the evidence so far.

 

[Rob Lister]

The spectrum of my observation runs on my encounter with ethnically-mixed offspring throughout my life. And I've payed closer attention recently with filipino/caucasian mixes because I myself will be having children like that.

Ultimately I guess, what are the "chances" I'll have a child with blue eyes who's mother is Asian?

If your wife is of Filipino decent (undefined) and you are of European decent (also undefined) then your kids will be brown or black-eyed beautiful people. Their hair shall be either dark black or, oddly, light brown: somewhat course in the former case, fine in the latter. Skin will be fair but will accept a tan like you've never seen. Male or female, they will be teases.

They will do well.

I know. I have three.

 

[chris epic]

If your wife is of Filipino decent (undefined) and you are of European decent (also undefined) then your kids will be brown or black-eyed beautiful people. Their hair shall be either dark black or, oddly, light brown: somewhat course in the former case, fine in the latter. Skin will be fair but will accept a tan like you've never seen. Male or female, they will be teases.

They will do well.

I know. I have three.

That's what I was thinking- I'm sure they'll be cool with or without blue eyes, because they'll be mine!

 

[chris epic]

• A number of genes are involved, interacting in a complicated way.
• Where identified, these genes tend not to have a simple, predictable effect, constant across all populations.
• We don't see any simple Mendelian inheritance pattern in skin colour.
• For parents with very different skin colours, the children tend not to resemble either very closely.
• Humans have the ability to alter their skin colour directly in response to the environment.

All of these are borne out by the evidence so far.

So environment still plays a part in skin colour, ragardless of genetic propensity? I mean, I know that our melanin reacts to UV rays, and we get "burnt" or "tan" or stay "fair" dependent on how much sun we get. But how we burn, or how good we tan, or how fair we stay, isn't that exclusively genetic?

 

[blutoski]

So environment still plays a part in skin colour, ragardless of genetic propensity? I mean, I know that our melanin reacts to UV rays, and we get "burnt" or "tan" or stay "fair" dependent on how much sun we get. But how we burn, or how good we tan, or how fair we stay, isn't that exclusively genetic?

Basically.

I think the key point that Lucky was trying to make was that there is no single gene for skin colour (last I heard, at least twenty), and when you see somebody of a particular shade, it's not clear if they inherited that exact shade, or if they just tanned that way instead.

I have a friend whose fraternal twins already obviously have very different skin tones and hair. Surprisingly, the girl has her father's light skin, but mother's african hair, while the boy has the mother's dark skin, and father's wavy hair. Both have caucasian noses, but african-like epicanthic eye folds.

 

[LostAngeles]

As far as dominant and recessive genes are concerned (which they aren't, because they're just genes, but that's beside the point)...

Genes that determine skin and eye color: since brown eyes and dark skin tend to be dominant over blue and green eyes and fair skin, would that imply that people with dark skin and eyes are genetically superior than those with fair skin and light-colored eyes?

Pigmentation in humans, like height, is determined by several alleles. They're not like handed-ness or tongue-rolling which is determined by dominant/recessive genes. Think of it like the greyscale using hexcode, or even simpler, binary. Say 0000 is white and 1111 is black. In between those you have 14 different colors. Where you decided what is dark and fair is entirely arbitrary, but you should be getting the idea.

Also, please stop learning about genetics from Metal Gear Solid.

 

[JoeTheJuggler]

As far as dominant and recessive genes are concerned (which they aren't, because they're just genes, but that's beside the point)...

Genes that determine skin and eye color: since brown eyes and dark skin tend to be dominant over blue and green eyes and fair skin, would that imply that people with dark skin and eyes are genetically superior than those with fair skin and light-colored eyes?

No. Evolution does not make judgments about "superior" or "inferior".

The closest you get to that is natural selection "deciding" which traits are more or less adaptive to a given environment. You might argue that since the light-colors are the more recessive that there are perhaps more environments where the darker pigmentations are adaptive. It certainly doesn't mean one is somehow universally superior to another.

BTW, skin and eye color are the result of much more complicated stuff than a single gene. I was going to elaborate, but Lucky and others already have.

 

[chris epic]

Also, please stop learning about genetics from Metal Gear Solid.

I like the binary analogy.

LOL- I don't get the reference, I don't play video games... I just wasn't equiped with the alleles; my genes repel them- but my brother and mother love them...

 

[chris epic]

You might argue that since the light-colors are the more recessive that there are perhaps more environments where the darker pigmentations are adaptive.

and/or larger populations....

I can understand that: by the time humans made it up into the icey lands of the north, Africa and Asia were more populated and/or their environment sustained them longer.

 

[LostAngeles]

I like the binary analogy.

LOL- I don't get the reference, I don't play video games... I just wasn't equiped with the alleles; my genes repel them- but my brother and mother love them...

In Metal Gear Solid, there's two characters that are clones of someone except one, "got all the dominant genes," and the other, "got all the recessive genes," and everywhere, heads exploded.

 

[Lucky]

Several people seem to have missed the point that (from common observation) dark skin as a trait is not dominant over fair skin (though for some of the genes involved, dark probably does correspond to dominant). Children of a dark and a fair-skinned parent tend to have skin colour in between (so there's little point in discussing the 'reasons' for this non-existent phenomenon). It's not very predictable, though, because (as has been explained), a number of genes are involved. However, the number can't be huge, or cases like these twins wouldn't occur.

So environment still plays a part in skin colour, ragardless of genetic propensity? I mean, I know that our melanin reacts to UV rays, and we get "burnt" or "tan" or stay "fair" dependent on how much sun we get. But how we burn, or how good we tan, or how fair we stay, isn't that exclusively genetic?

My point was that environment plays an important part in skin colour (less so for very dark people) – you couldn't (even in principle) look at a random person's DNA and predict their current skin shade very accurately. Eye colour is different – it's not affected by any normal environmental factors. I don't think the reasons for this difference are completely understood (and it's a long way out of my field). But it seems likely that it arose least partly because the match of skin colour to environment is important, with quite strong selection pressures in both directions, and that doesn't apply to eye colour. Fine-tuning of skin colour is facilitated both by multiple genes that interact, and by a strong immediate (non-inherited) response in the individual.

In Metal Gear Solid, there's two characters that are clones of someone except one, "got all the dominant genes," and the other, "got all the recessive genes," and everywhere, heads exploded.

That much stupid I will never understand. I mean, if they thought it was a good idea to mention dominant and recessive genes, why didn't they think it mattered to find out what they were talking about?

 

[Silly Green Monkey]

Incidently, the gene that controls melanin production has six alleles. So, a person with all dominant alleles will be dark brown, one with all recessive alleles will be pale brown. It's quite possible for siblings to get different mixes of dominant and recessive alleles from the same parents, though most people don't believe them.