Basic Question: Traits

[Art64mo]

Hi All,

 

I am afraid I am not a geneticist, or even educated in genetics. My question is basic about the percentage of genetic traits being passed on to next generation.

 

An ancestor was 1/16th American Indian, remainder of genetic mack up was Caucasian. He married a 100% Caucasian woman and had five (5) children between 1908 & 1920.

Of the 5 children, 2 children displayed American Indian traits, which includes darker skin color, black hair and high cheekbones. Appearance of 1/2 Cherokee Indian.

It would seem to me that the high cheekbones and black hair could be normal, but not the darker Indian like skin color.

Question: Can someone possibly give me the genetic trait percentage that this man could possibly pass onto his children at 1/16th Cherokee Indian?

High Cheekbone: ??%
Black Hair: ??%
Darker Indian Skin Color: ??%

Thank you very much. Your answer will help me determine if he was the father of the two children in question.

Respectfully,
Art

[chadn737]

Its honestly hard to know because of recombination. In theory, the odds are that you are 1/4 the genetic makeup of any grandparent...but that is the probability of this occurring. In reality, the percentage that you inherit from your grandparents will vary, as will what you inherit from your great grandparents, great great grandparents, etc. These are also complex traits, which makes the situation even more complex. Plus there is population structure, its not the case that certain alleles are exclusive to certain populations.

[Art64mo]

Hi chadn737,

 

Thank you for your reply. However, as a non Geneticist, your reply "SOUNDS" like you are saying that a son, born to a father with 1/16th Cherokee Indian heritage "COULD" cast a son with most Indian traits, like darkened skin tone. I do realize black hair and high cheekbones would be more dominant.

 

We are trying to determine in the ancestor in question was the father of the son or if the son had been adopted. If I am correct in what I think you are saying, then you have answered my question.

 

Respectfully,

Art

[overtone]

 

 

It would seem to me that the high cheekbones and black hair could be normal, but not the darker Indian like skin color.

If you have connection to enough descendents, you might try a DNA family map comparing the progeny of the 2 to the 3 - the simple description above carries a lot of unknowns (such as exactly what is meant by "100% Caucasian", and how sure you are of that description as well as "normal" in general).

 

Here's an example of "100% Caucasian" people, to compare with the children of the Cherokee: http://www.google.com.au/imgres?imgurl=http%3A%2F%2Fthumbs.dreamstime.com%2Fz%2Ftraditional-latvian-folk-dancing-6683912.jpg&imgrefurl=http%3A%2F%2Fwww.dreamstime.com%2Fstock-photography-traditional-latvian-folk-dancing-image6683912&h=534&w=800&tbnid=_4ocH56r6XeVSM%3A&zoom=1&docid=ATnEEzHTXoircM&ei=iGR6U9LYOdOMyATR1oKoBg&tbm=isch&ved=0CLsBEDMoWzBb&iact=rc&uact=3&dur=1554&page=4&start=71&ndsp=25

[Ten oz]

*Disclaimer* I am an electrician not a genealogist.

 

If we assume evolution is true (which I do) than all humans are one species with a common ancestor. That common ancestor is believed to have arisen on the continent of Africa. As such all humans have genes from those darker haired, tanned skin, brown eyed ancestors.

So even a child born with blue eyes from blue eyed parents carriers brown eyed genes. So in biracial children the math isn't straight forward as 50/50. All humans are ultimately related if we go far enough back and we mix the batch everytime we mate so isolating the odds of which traits should appear and when is tough.

Edited May 31, 2014 by Ten oz

[chadn737]

Hi chadn737,

 

Thank you for your reply. However, as a non Geneticist, your reply "SOUNDS" like you are saying that a son, born to a father with 1/16th Cherokee Indian heritage "COULD" cast a son with most Indian traits, like darkened skin tone. I do realize black hair and high cheekbones would be more dominant.

 

We are trying to determine in the ancestor in question was the father of the son or if the son had been adopted. If I am correct in what I think you are saying, then you have answered my question.

 

Respectfully,

Art

 

Yes, he could, but it is unlikely. Furthermore, the father will not be exactly 1/16th Cherokee. Because of recombination he could be more, but more likely it is less.

[Delta1212]

*Disclaimer* I am an electrician not a genealogist.

 

If we assume evolution is true (which I do) than all humans are one species with a common ancestor. That common ancestor is believed to have arisen on the continent of Africa. As such all humans have genes from those darker haired, tanned skin, brown eyed ancestors.

So even a child born with blue eyes from blue eyed parents carriers brown eyed genes. So in biracial children the math isn't straight forward as 50/50. All humans are ultimately related if we go far enough back and we mix the batch everytime we mate so isolating the odds of which traits should appear and when is tough.

Genes are discrete units of inheritance (more or less). You don't have all of your ancestors' genetic material in you, even in some reduced form. You either inherit a particular allele or you do not. It is entirely possible that if you go back far enough you could find an ancestor that contributed nothing that survived all the way to end up in your DNA.

 

Essentially, just because you had brown eye-ed ancestors does not necessarily mean you have a brown-eyed gene buried somewhere in your DNA.

[Ten oz]

Genes are discrete units of inheritance (more or less). You don't have all of your ancestors' genetic material in you, even in some reduced form. You either inherit a particular allele or you do not. It is entirely possible that if you go back far enough you could find an ancestor that contributed nothing that survived all the way to end up in your DNA.

Essentially, just because you had brown eye-ed ancestors does not necessarily mean you have a brown-eyed gene buried somewhere in your DNA.

You may very well be 100% correct. My understand has been that all the information is there in DNA only much of it isn't expressed. Like the experiments performed to grow teeth in chickens by biologist Mathew Harris. Birds no longer have trigger the growth of teeth but the ability/genes for them to do so is still in their DNA.

[Delta1212]

You may very well be 100% correct. My understand has been that all the information is there in DNA only much of it isn't expressed. Like the experiments performed to grow teeth in chickens by biologist Mathew Harris. Birds no longer have trigger the growth of teeth but the ability/genes for them to do so is still in their DNA.

DNA doesn't retain a complete history of everything that has come before it. However, sometimes it's useful for an organism to eliminate some trait. You can do that by eliminating the genes that code for that trait, or you can do it by suppressing them. As long as the disadvantageous trait is no longer present, evolution isn't too picky about the how.

 

So you can certainly wind up with past traits that no longer get expressed buried in DNA, but it's because they received the evolutionary equivalent of white out rather than backspace to get rid of them. If the bits of DNA in question aren't used for anything else, they probably will get lost eventually just because any mutations that affect them probably won't impact the organism in any significant way, but in the meantime, they are technically still present.

 

That said, again, it's because genetic material is messy and not terribly picky about what is and is not included as long as the final product works, and not because there is any retention of all historical traits in your DNA. Some stuff gets dropped, some stuff gets altered, some stuff gets overwritten.

 

Edit: Here, better metaphor.

 

You've got a ton of papers on your desk. You don't need some of them and, not being super organized, you chuck some of them in the trash and throw others in a desk drawer with a bunch of other junk you never look at.

 

Technically, the stuff you threw in the desk drawer is still accessible, but you probably won't ever see it again and will eventually wind up in the trash during a periodic cleaning out of the desk. It would not be accurate to describe your junk drawer as a complete history of all of your paperwork just because you stuffed a few things you didn't want cluttering the top of your desk in the junk drawer instead of throwing them away outright.

Edited May 31, 2014 by Delta1212