Mike
Well-known member
http://www.sciencedaily.com/releases/2008/01/080130170343.htm
I have a serious and hopefully thought provoking question, how can a genetic mutation add genetic information?Silver said:I thought it was interesting. If it's true it raises some questions about the blue eyed Indians that were living here when the first Europeans arrived. :shock:
redrobin said:I have a serious and hopefully thought provoking question, how can a genetic mutation add genetic information?Silver said:I thought it was interesting. If it's true it raises some questions about the blue eyed Indians that were living here when the first Europeans arrived. :shock:
Possibly but why would a large percentage of the worlds population now contain the mutation if that's the case? Survivability doesn't increase with blue eyes. As a matter of fact, I'd suspect that blue eyes are on the decline. I'd guess that they have been on the decrease since creation. Blue eyes were genetically available at creation and genetic information in general has been decreasing since then.Mike said:redrobin said:I have a serious and hopefully thought provoking question, how can a genetic mutation add genetic information?Silver said:I thought it was interesting. If it's true it raises some questions about the blue eyed Indians that were living here when the first Europeans arrived. :shock:
Polymorphism?
redrobin said:Possibly but why would a large percentage of the worlds population now contain the mutation if that's the case? Survivability doesn't increase with blue eyes. As a matter of fact, I'd suspect that blue eyes are on the decline. I'd guess that they have been on the decrease since creation. Blue eyes were genetically available at creation and genetic information in general has been decreasing since then.Mike said:redrobin said:I have a serious and hopefully thought provoking question, how can a genetic mutation add genetic information?
Polymorphism?
I'd be interested in seeing the research. Please present the scientific answer as to why so many blue eyes from a mutation?Mike said:redrobin said:Possibly but why would a large percentage of the worlds population now contain the mutation if that's the case? .Mike said:Polymorphism?
Thanks for your input, but I think I'll rely on the research as written. :wink:
.
redrobin said:I'd be interested in seeing the research. Please present the scientific answer as to why so many blue eyes from a mutation?Mike said:redrobin said:Possibly but why would a large percentage of the worlds population now contain the mutation if that's the case? .
Thanks for your input, but I think I'll rely on the research as written. :wink:
.
Denny said:I thought we all traced back to Adam and Eve
The laws of genetics state that eye color is inherited as follows:
1-If both parents have blue eyes, the children will have blue eyes.
2-The brown eye form of the eye color gene (or allele) is dominant, whereas the blue eye allele is recessive.
3-If both parents have brown eyes yet carry the allele for blue eyes, a quarter of the children will have blue eyes, and three quarters will have brown eyes.
When an asian has a child with a non asian, the offspring still has thicker hair, etc. When a blue eyed person has a child with a brown eyed person (remember that was all there was in your scenario) you get brown eyes with a blue eye recessive gene. Seems to me that it'd be hard to start blue eyes from that deal. I'm not a geneticist though and don't understand all I should. Please explain more.Mike said:redrobin said:I'd be interested in seeing the research. Please present the scientific answer as to why so many blue eyes from a mutation?Mike said:Thanks for your input, but I think I'll rely on the research as written. :wink:
.
Same reason Asians have thicker hair shafts, smaller breasts, more fat cover on the eyelids, an increase in sweat glands, etc. etc. ?
http://www.nytimes.com/2013/02/15/science/studying-recent-human-evolution-at-the-genetic-level.html?_r=0
Abstract from the peer reviewed research:
http://www.cell.com/abstract/S0092-8674%2813%2900067-6
You'll have to pay for the whole study. :lol:
With who?Mike said:Maybe those blue eyed people were "Linebreeding"? :lol:
People with blue eyes have a single, common ancestor, according to new research.
A team of scientists has tracked down a genetic mutation that leads to blue eyes. The mutation occurred between 6,000 and 10,000 years ago. Before then, there were no blue eyes.
"Originally, we all had brown eyes," said Hans Eiberg from the Department of Cellular and Molecular Medicine at the University of Copenhagen.
The mutation affected the so-called OCA2 gene, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin.
"A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a 'switch,' which literally 'turned off' the ability to produce brown eyes," Eiberg said.
The genetic switch is located in the gene adjacent to OCA2 and rather than completely turning off the gene, the switch limits its action, which reduces the production of melanin in the iris. In effect, the turned-down switch diluted brown eyes to blue.
If the OCA2 gene had been completely shut down, our hair, eyes and skin would be melanin-less, a condition known as albinism.
"It's exactly what I sort of expected to see from what we know about selection around this area," said John Hawks of the University of Wisconsin-Madison, referring to the study results regarding the OCA2 gene. Hawks was not involved in the current study.
Baby blues
Eiberg and his team examined DNA from mitochondria, the cells' energy-making structures, of blue-eyed individuals in countries including Jordan, Denmark and Turkey. This genetic material comes from females, so it can trace maternal lineages.
They specifically looked at sequences of DNA on the OCA2 gene and the genetic mutation associated with turning down melanin production.
Over the course of several generations, segments of ancestral DNA get shuffled so that individuals have varying sequences. Some of these segments, however, that haven't been reshuffled are called haplotypes. If a group of individuals shares long haplotypes, that means the sequence arose relatively recently in our human ancestors. The DNA sequence didn't have enough time to get mixed up.
"What they were able to show is that the people who have blue eyes in Denmark, as far as Jordan, these people all have this same haplotype, they all have exactly the same gene changes that are all linked to this one mutation that makes eyes blue," Hawks said in a telephone interview.
Melanin switch
The mutation is what regulates the OCA2 switch for melanin production. And depending on the amount of melanin in the iris, a person can end up with eye color ranging from brown to green. Brown-eyed individuals have considerable individual variation in the area of their DNA that controls melanin production. But they found that blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes.
"Out of 800 persons we have only found one person which didn't fit — but his eye color was blue with a single brown spot," Eiberg told LiveScience, referring to the finding that blue-eyed individuals all had the same sequence of DNA linked with melanin production.
"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said. "They have all inherited the same switch at exactly the same spot in their DNA." Eiberg and his colleagues detailed their study in the Jan. 3 online edition of the journal Human Genetics.
That genetic switch somehow spread throughout Europe and now other parts of the world.
"The question really is, 'Why did we go from having nobody on Earth with blue eyes 10,000 years ago to having 20 or 40 percent of Europeans having blue eyes now?" Hawks said. "This gene does something good for people. It makes them have more kids."
redrobin said:When an asian has a child with a non asian, the offspring still has thicker hair, etc. When a blue eyed person has a child with a brown eyed person (remember that was all there was in your scenario) you get brown eyes with a blue eye recessive gene.