The Importance of Skin Color on Women's Health
Posted by on October 10, 2012 - 12:56pm

On Monday, The Scientist printed a valuable article linking to a TED video and a new book entitled Living Color by Nina Jablonski. The video and book delve into the importance of skin color and types for health and social well-being.

To me, there are three points of greatest value: 1) that as humans, our personal melanin and intake of ultraviolet radiation (UVR) are vitally important to our individual health, 2) that as migration and evolution has occurred our pigmentation gene is exceptionally labile, and 3) that skin pigmentation and our individual variations are not discussed nearly enough in our society.

Although I am an advocate for more open, honest dialogue about the significant role race has in this country, this argument for better quality health is different. We need to begin also addressing what pigmentation means for the individual and how women have varying skin needs.  This message is not about Black, White, Asian, Latino, or any other socially constructed label for race or ethnicity, this is about individual health concerns.

As the author correctly explains, the MC1R gene, which is the gene predominantly responsible for pigmentation, has little variation in African people. Those with darker (or more melanin-rich) skin have a “built-in defense” against harmful ultraviolet radiation, is often ideal for health and normal cell reproduction. However, as humans migrated and evolved there was a depigmentation of skin, leading to lightly pigmented (or melanin-poor) peoples. This mismatch of genetic predisposition and solar regimes can mean very different things for a woman’s health.

For example, Nina Jablonski asserts that, “People of Northern European ancestry, for instance, living in Florida or Australia confront intense UVR conditions with pale, melanin-poor skin and suffer from sunburns, high rates of skin cancer, and accelerated skin aging. People of central African or southern Indian ancestry living in Wisconsin or Wales face low and highly seasonal UVR conditions with exquisitely sun-protected skin and suffer from vitamin D deficiencies as a result.”

Ladies, knowing your body also means knowing the health risks and benefits associated with your skin.  Remember, your skin is the largest organ in your body, talk to your health care providers and keep yourself safe!

The mysteriously evolving Y chromosome…
Posted by on January 18, 2010 - 8:52am

I know what you’re thinking, this is a Women’s Health Blog - but we like men here too.  A recent study published in Nature (and featured in the New York Times) reveals some interesting new insight into the X-chromosome’s somewhat puny-looking counterpart.  Researchers Jennifer Hughes and David Page at the Whitehead Institute have discovered that the Y-chromosome appears to be evolving much faster than the rest of the genome.

Humans have 23 pairs of chromosomes (46 total); two of those chromosomes, called the sex chromosomes, are responsible for determining the sex of a human. Women have two of the same chromosomes, named X (see “What’s with the dancing X chromosomes?"), while men have one X chromosome and one Y chromosome, thus resulting in a mismatched pair.  Scientists have known for quite some time that the Y chromosome originally contained the same genes as the X chromosome, but has lost most of those genes through evolution.  Because of this, scientists have believed that the Y chromosome has been degrading through gene loss and has reached, or will reach a static state.

This new research however may prove otherwise.  In their study, Drs. Page and Hughes compared the genetic makeup of the human and the chimp.  Since chimps and humans shared a common ancestor just six million years ago, the differences in the genomes can help determine rates of evolution in the species.  The researchers found that while the chimp and human genomes differed in less than 1 percent of their DNA, comparison of the Y-chromosomes shows a difference of 30%.  This data indicates that this chromosome in particular is not static, but is in fact evolving at a greater rate than the rest of the genome.

The researchers suggest that some of this rapid evolutionary diversity might be attributable to differences in the mating patterns of humans and chimps and the large role of genes on the Y chromosome in sperm production.  A unique feature of the Y chromosome is that because it occurs in a mismatched pair with the X chromosome, it cannot exchange genes (called crossing-over) prior to meiotic cell division the way that the other twenty-two chromosomes do.   This places increased selective pressure on the Y chromosome, since a change in one gene must affect the reproductive fitness of the others.  In addition, the structure of the Y chromosome provides it with the opportunity to exchange genes with itself, which could accelerate the rate of change in its genetic sequence.

So does this mean that men are evolving faster than women?  No it doesn’t (sorry guys).  However, according to Andrew Clark, a geneticist at Cornell University (see NYT article), the rapid changes of the Y chromosome could have broader effects on the rest of the human genome.  Only further research will tell…