Monday, December 8, 2008

Are Redheads Descended from Neanderthals?

In 2003, Dr. Rosalind Harding, a quantitative geneticist from the Institute of Molecular Medicine at Oxford, estimated that the age of the red hair variants or alleles of the Melanocortin 1 Receptor gene were as follows:

Assumption 1: If MC1R red hair variants evolved in a human population of constant size, then the gene could be approximately 40,000 years or older and may come from a Neanderthal origin.

Assumption 2: If MC1R red hair variants evolved in a population that has been expanding exponentially, then the gene could be less than 40,000 years old and may come from early humans or Cro-Magnon.

Assumption 3: If MC1R red hair variants were under positive selection or favored in evolution then the gene can be as young as 10,000 years.

The mere suggestion that redheads are descended from Neanderthals may offend you or if you have more genetic knowledge, you might think it genetically impossible. For a while, I have to admit that I was quite intrigued by the idea of being descended from Neanderthals. I thought that it might explain why I always felt like an alien. If redheads were “the others’ (to use a Lost reference) then that might explain why people have been superstitious about us throughout time. Then again, our pitiful numbers (2% of the world’s population) may also be the cause for superstition.

However, with the publication of the October 2008 issue of National Geographic, the Neanderthal-Redhead connection was supposedly “myth-busted.” Researchers conducted DNA tests on Neanderthal remains and while it was discovered that they were indeed redheads (very exciting!), apparently they had independently evolved their own red hair variants that were completely different than the human red hair variants. If both Neanderthals and humans independently evolved red hair variants, then this may support that there is an evolutionary advantage to red hair, such as the ability to produce more vitamin D with less sunlight exposure.

But, for some reason when I read this, I still did not want to let the Neanderthal-Redhead theory go. They haven’t DNA tested every single Neanderthal that walked the earth. For all we know, maybe Neanderthals had triple the red hair variants than humans have. Humans may have only inherited 5 of the Neanderthal's multiple red hair variants and did NOT inherit the ONE Neanderthal red hair variant that scientists just happened to discover on that particular day. But who am I to argue with scientists?

Then in January 2010, Alan Alda hosted this great series on PBS entitled "The Human Spark". Apparently, what distinguishes early modern humans from Neanderthals includes the human ability to be more innovative with technology, their complex human social structure, and their ability to be artistic. So then it seemed like the Neanderthal-Redhead connection was very unlikely because, as you know already, redheads are some of the most artistic and technologically and socially savvy humans there are. So I threw my arms up and gave up UNTIL......

The October 2010 edition of Discover magazine states that early humans and Neanderthals mated after all! Evolutionary geneticist Svante Paabo and colleagues at the Max Planck Institute for Evolutionary Anthropology in Germany analyzed DNA fragments from Neanderthal bones and traced Neanderthal and human interbreeding back by 60,000 years to the Middle East. Apparently, 1 to 4 percent of the human genome outside of Africa is Neanderthal!!! The gene flow between humans and Neanderthals most likely occurred as humans were migrating to Europe, Asia, and New Guinea.

Now the question is whether the 1 to 4 percent of the human genome that is Neanderthal in origin includes the 5 human red hair variants of the MC1 receptor gene, which are responsible for creating about 2 percent of the world's population -- Redheads!

Um......or something like that....? Ow, my brain, it hurts.

Sunday, December 7, 2008

Red Hair Inheritance

If both parents provide a red hair allele of their MC1R gene, the child will have red hair. If one parent provides a red hair allelle and the other parent provides a non-red hair allele, the chance of the child having red hair increases but is not a certainty. Sometimes if only one red hair allele is present, the red hair may show up in a less obvious manner, such as highlights in a beard.

My Mom is an Italian-Polish brunette with an olive complexion, and up until my Dad lost all of his hair in his thirties, he was a fair-skinned Czech blonde. BUT my Aunt Delores on my mother's side was a redhead. From that, I know for certain that at least one of my red hair alleles came from my Grandpa Leo, the Italian. Sometime in the 1950s, Grandpa Leo, Grandma Helen and Uncle Ronny traveled to Grandpa's home town of Lucca, Italy. Grandma Helen used to tell me that many of my cousins there had red hair. Since Grandpa Leo had about 15 brothers and sisters, I imagine there may be quite a bit of redheads in the larger family by now. Grandma Helen was also very surprised to board a bus in Lucca to find it full of redheads! So I guess that's where Titian got his inspiration!!! Incidentally, I also had a great uncle that delivered bread to Puccini's house in Lucca. Every time anyone in my family hears or sings Puccini, we all break down crying including me at a recital about 13 years ago, but that's another story.

Regarding my Dad's side of the family, he doesn't seem to recall any redheaded relatives, but according to the above, a red hair allele from one parent may dominate the fair-blonde allele from another parent so that the red "shines through". I recently read my Grandma Anna's journal. About 100 years ago, she worked 7 days a week, 12 hours a day, farming sugar beets and working in a sugar factory in Prisnotice, Moravia. She moved to the United States, studied English and Italian, and became one of the first social workers in Pittsburgh, PA. She assisted immigrant workers and their families, many of whom were injured in steel mills and coal mines. So to me, Grandma Anna Hornicek Sirney is an honorary redhead for her courage, love, hard work, and inspiration.

So where does your red hair inheritance come from?

Red Hair Gene Discovery

In 1995, the Department of Dermatology at Edinburgh University headed by Professor Jonathan Rees successfully identified the gene responsible for pigment production, the melanocortin 1 receptor. The melanocortin 1 receptor gene or MC1R is a genetically encoded protein that all humans have in pairs, one donated by each parent. Professor Rees and his lab discovered that four to five common variations of MC1R are responsible for the production of red hair. All of the red hair variants (or alleles) of the MC1R gene cause the receptor to not function.

When I first started venturing down the path of studying the relationship of red hair to health, I was so excited to find out about the discovery of our red hair variants! Because red hair is a relatively rare mutation, it makes it easier for scientists to spot. The last I checked they still were trying to isolate blonde hair variants; and the combination of pale skin and dark hair completely perplexes them.

When you do a search on PubMed, there are so many studies published about MC1R. When I first delved into this research, I was completely overwhelmed and didn't understand a dang thing I read. Only after taking a human physiology class, was I able to begin understanding the studies about MC1R. My challenge in this blog will be to convey the information that I have learned in an understandable way. So if I don't make sense or you go "huh?" - just let me know.