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Blonde - The Genetic Reason

slo1
Posts: 4,359
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6/3/2014 1:05:52 PM
Posted: 2 years ago
http://www.sciencedaily.com...

The study shows that even small, tissue-specific changes in the expression of genes can have noticeable morphological effects. It also emphasizes how difficult it can be to clearly connect specific DNA changes with particular clinical or phenotypic outcomes. In this case, the change is subtle: A single nucleotide called an adenine is replaced by another called a guanine on human chromosome 12. The change occurs over 350,000 nucleotides away from the KITLG gene and only alters the amount of gene expression about 20 percent -- a relatively tiny blip on a biological scale more often assessed in terms of gene expression being 100 percent "on" or "off."

"What we're seeing is that this regulatory region exercises exquisite control over where, and how much, KITLG expression occurs," said Kingsley. "In this case, it controls hair color. In another situation -- perhaps under the influence of a different regulatory region -- it probably controls stem cell division. Dialing up and down the expression of an essential growth factor in this manner could be a common mechanism that underlies many different traits."

Kingsley is known for his studies of the evolution of a tiny fish called the threespine stickleback. The stickleback adapts quickly to changes in its environment. It becomes darker in murky lakes, and develops modified spine, fin and armor structures in response to different types of predators. Kingsley's research has shown that these adaptive changes are often driven by changes in the regulatory regions that surround and control gene expression, rather than within the coding regions of the genes themselves.
slo1
Posts: 4,359
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6/3/2014 1:10:55 PM
Posted: 2 years ago
The article says it nicely. It is interesting how a change in one base pair can have such a subtle change. Also interesting that the change reduces the gene expression, AKA less of that protein created, rather than completely stops it.

I'm also amazed at the duel use this protein has, although one could argue that hair color has no purpose and is just a residual consequence of no consequence.

Lots of complexity going on with gene expression.