Thursday, March 21, 2019

Baby's got Blue Eyes

Blue-eyed Girl (Me)
So recently I discovered that I can watch full episodes of TV shows on YouTube that I used to watch as a teenager and a young adult, so I have been watching many of my favourites: Western and Science Fiction TV shows over the last few weekends. It struck me as I watched the shows that many of the principal actors had blue eyes even those who had dark hair.

So since you can Google anything, I wondered if there are fewer blue-eyed people and yes, there are. One web site said 100 years ago in the United States, half the population had blue-eyes and, in 2010, only 1 in 6 had blue eyes.  Of course, there's also the fact that now on television there's more racial diversity rather than actors predominantly of Western European descent. 

But what's more interesting is that blue eyes haven't been around all that long, only about 10,000 years and apparently we all have one common ancestor.

 "Every blue-eyed person on the planet is descended from a single European who lived around 6,000 to 10,000 years ago, and who first developed a specific mutation that accounts for the now widespread iris coloration.

Originally, all humans had brown eyes, although genetic variation relating to a gene called OCA2 resulted in changes to the amount of pigment produced by different individuals, resulting in the emergence of different shades of brown. Armed with this information, scientists had for many years searched for the source of blue eyes on the OCA2 gene, but without success.
More recently, a mutation to a separate, nearby gene called HERC2 has been identified as the cause of blue eyes. This alteration switches off OCA2, the gene that determines the amount of the brown pigment melanin that we make. It is thought to have first occurred when humans began to migrate from Africa to Europe, meaning that every person with blue eyes is a descendent of a single early European.
The fact that every blue-eyed person alive today has this same mutation is pretty compelling evidence for this theory, although the identity of the initial mutant remains something of a mystery. To date, the earliest set of sapphire-colored peepers ever found belong to a 7,000-year-old skeleton that was discovered in northern Spain. Naturally, the eyes had long since decayed, however genetic analysis revealed that they would have appeared blue in color."
Will blue-eyes ever become extinct, other web sites I found say "no" unless that gene mutation changes again. But we are pretty rare, world wide only 8% of people carry the gene for blue-eyes and it's recessive so they may not have blue eyes themselves.
So anyway, next time you see another blue-eyed person, you can say "Hi Cousin".
 And see if you can guess what TV shows I've been watching?


  1. That is very interesting information about blue eyes. Mom is totally blue-eyed. Each of us is bi-eyed, except Timber's brown eye has a tinge of blue , so he is bi-eyed and parti-eyed:)

    Woos - Lightning, Misty, and Timber

    1. I wonder if the genetics of eye color is the same for dogs. Something else to Google.

  2. Mom says, "Hi Cousin"! She has blue eyes too! What an interesting post!

  3. Oh interesting. We all have brown eyes in this family. Not much diversity here :)

  4. I didn't know you could do that, watch old shows on Youtube. I'll have to investigate!


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