Tag Archive blue


Scientists found something huge..

…..that all blue-eyed people have in common

Scientists working to uncover our DNA history.

You’ve probably wondered, why do we have the colour eyes we do? It comes down to our genes. And scientists are really starting to get to the bottom of it.

Produced By Matt Johnston. Research by Lauren Friedman. 

RABGGTA is a candidate gene for hair color.

Originally posted by businessinsider.com

New research shows that people with blue eyes have a single, common ancestor. A team at the University of Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blueeyed humans alive on the planet today.

Studies carried out by scientists from the Institute of Forensic Genetics at the University of Copenhagen have concluded that all blue-eyed people share a common ancestor, someone who lived 6,000 to 10,000 years ago near the area by the Black sea.

Researchers analyzed and compared the unique genetic make-up of the chromosomes in the iris from 155 blue-eyed individuals from diverse regions such as Denmark, Turkey and Jordan.

All of the subjects that participated in the study had the exact same genetic “mutations” in specific chromosomes of the eye with very little variation on the genes, indicating that the “mutation” responsible for blue-eyes first arose and spread relatively recently.



The human eye color is a quantitative trait displaying multifactorial inheritance. Several studies have shown that the OCA2 locus is the major contributor to the human eye color variation. By linkage analysis of a large Danish family, we finemapped the blue eye color locus to a 166 Kbp region within the HERC2 gene. By association analyses, we identified two SNPs within this region that were perfectly associated with the blue and brown eye colors: rs12913832 and rs1129038. Of these, rs12913832 is located 21.152 bp upstream from the OCA2 promoter in a highly conserved sequence in intron 86 of HERC2. The brown eye color allele of rs12913832 is highly conserved throughout a number of species. As shown by a Luciferase assays in cell cultures, the element significantly reduces the activity of the OCA2 promoter and electrophoretic mobility shift assays demonstrate that the two alleles bind different subsets of nuclear extracts. One single haplotype, represented by six polymorphic SNPs covering half of the 3? end of the HERC2 gene, was found in 155 blue-eyed individuals from Denmark, and in 5 and 2 blue-eyed individuals from Turkey and Jordan, respectively. Hence, our data suggest a common founder mutation in an OCA2 inhibiting regulatory element as the cause of blue eye color in humans. In addition, an LOD score of Z = 4.21 between hair color and D14S72 was obtained in the large family, indicating that



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Blue eyes were not always around!

Before we get into that, let’s talk about the science behind blue eyes and why they look blue.The iris is made up of two separate layers: the epithelium in the back and the stroma in the front. The epithelium is composed of black-brown pigments and is only two cells thick. Some people have dark specks in their eyes. This is the epithelium showing through.The stroma is made of colorless collagen fibers. Sometimes the pigment melanin is present, and sometimes it contains excess collagen deposits. It is these two things, melanin and collagen, the determine the color of a person’s eyes.


According to Science Alert“Blue eyes are potentially the most fascinating, as their colour is entirely structural. People with blue eyes have a completely colourless stroma with no pigment at all, and it also contains no excess collagen deposits. This means that all the light that enters it is scattered back into the atmosphere, and as a result of the Tyndall effect, creates a blue hue. Interestingly, this means that blue eyes do not actually have a set colour — It all depends on the amount of light available when you look at them.”

If you think about that for a second, it is really awesome!

However, where did blue eyes come from?

According to recent research, all people with blue eyes come from one common ancestor!

“New research shows that people with blue eyes have a single, common ancestor. Scientists have tracked down a genetic mutation which took place 6,000-10,000 years ago and is the cause of the eye color of all blue-eyed humans alive on the planet today.” (Source)

It should also be noted that even though blue eyes are becoming more and more rare, it is unlikely that they will disappear forever. (Can you believe they started from one person!)

Originally posted at davidwolfe.com


Interesting info.

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