Redhead Genes

There are definitely redheads in my family!  And there is red in the hair of my grandchildren and one
is (the little girl born 2 years ago on my birthday) is VERY red-haired.  So even though my daughter

in-law has ash tones to her blonde hair, there’s a redhead in her ancestry somewhere.  Even the brunettes

in my family, including descendants,  had (have) red tones.  My brothers have red beards …..

Are You Carrying the Redhead Gene?

Some parents worry that their children will be born with a rare disease or a hidden genetic disorder. Other parents, however, wonder if their children will possess something more obvious: red hair.

A British ancestry company, BritainsDNA, is now offering parents the chance to see if their children might inherit the so-called “ginger gene,” the Telegraph reports. The test will scan each parent’s DNA for signs of the so-called MC1R gene that causes redheadedness.

“Through a simple saliva test to determine deep ancestry, we can … identify whether an individual is a carrier of any of the three common redhead variants in the gene MC1R,” said Dr. Jim Wilson, chief scientist at BritainsDNA, as quoted in the Huffington Post.

PHOTOS: Evolution Before Your Eyes

The gene for red hair is recessive, so a person needs two copies of that gene for it to show up or be expressed. That means even if both parents carry the gene, just one in four of their children are likely to turn out to be a redhead. As a result, families that have no redheads for decades can suddenly discover a carrottop in their midst.

“Families can carry a variant for generations, and when one carrier has children with another carrier, a redheaded baby can appear seemingly out of nowhere.” Wilson said, as quoted in the Daily Mail.

Though there’s no scientific evidence that redheads deserve their reputation for having fiery temperaments, some recent reports suggest having red hair is associated with a number of health issues. A study from the journal Nature found that the pigment pheomelanin, which is responsible for red hair, may also make redheads even more susceptible to melanoma than fair-skinned blondes, according to the Los Angeles Times.

Sperm Bank Rejects Redheads

And a widely reported study from the Journal of the American Dentistry Association found that redheads are more sensitive to pain and require extra anesthesia during surgery, according to ABC News.

But there may be some advantages to having red hair, too, EverydayHealth.com reports. The pale skin that redheads usually have is more efficient at soaking up sunlight — and sunlight is required for the body to manufacture vitamin D, an essential nutrient.

Worldwide, red hair is quite rare, and just over 0.5 percent, or one in 200 people, are redheads — this amounts to almost 40 million people, the Daily Mail reports.

In Ireland, an estimated 10 percent of the population has red hair, though about 40 percent of the Irish carry the recessive gene. In Scotland and England, 13 percent and 6 percent, respectively, are redheaded, according to the Daily Mail.

The DNA test will be offered by BritainsDNA at a genealogy and ancestry exhibition named Who Do You Think You Are, associated with the popular NBC television show and scheduled to be held in London next month.

This article originally appeared on LiveScience.com.

More From LiveScience.com:

Inbreeding Not Such a Good Idea

http://blogs.smithsonianmag.com/science/2009/04/royals-prove-inbreeding-is-a-bad-idea/

April 16, 2009

Royals Prove Inbreeding Is a Bad Idea

Those jokes about inbred royals might have some basis in fact, according to a  new study in the journal PLOS One .

The Hapsburg dynasty ruled Spain from 1516 to 1700, reigning over the height of the  Spanish empire. The dynasty ended when the last king, Charles II, who suffered  physical and mental disabilities, died without issue despite two marriages.  Inbreeding had been thought to play a role in the family’s extinction.

A young Charles II, c. 1673, via Wikimedia Commons

A young Charles II, c. 1673, via Wikimedia  Commons

A group of biologists from Spain developed an extended pedigree of more than  3,000 individuals over 16 generations so that they could calculate the  “inbreeding coefficient” of the Spanish Hapsburg kings. The inbreeding  coefficient is a measure of relatedness between two individuals. Here’s an example:

Take a first-cousin mating. First cousins share a set of grandparents. For  any particular gene in the male, the chance that his female first cousin  inherited the same gene from the same source is 1/8. Further, for any gene the  man passes to his child, the chance is 1/8 that the woman has the same gene and  ½ that she transmits that gene to the child so 1/8 X ½ = 1/16. Thus, a  first-cousin marriage has a coefficient of inbreeding F =1/16  [0.0625].

The six kings of Spain married a total of 11 times. Nine of the marriages  were “consanguineous unions in a degree of third cousins or closer.” There were  even two uncle-niece unions (eww). Over time, the biologists calculated, the  inbreeding coefficient rose from 0.025 for Philip I, the founder of the dynasty,  to 0.254 for Charles II. His inbreeding coefficient–0.254–is as high as that  expected from a parent-child or a brother-sister relationship (double eww).

In addition to the high inbreeding coefficients, the biologists cited two  other lines of evidence that inbreeding was the cause of the Spanish Hapsburgs’  demise: First, the family experienced a high rate of infant mortality, with half  of the children failing to reach age one (compared with 80 percent survival at  that time in Spanish villages). Second, many of Charles II’s disabilities and  illnesses–short stature, weakness, intestinal problems, sporadic hematuria,  impotence/infertility–could be explained by two genetic disorders, combined  pituitary hormone deficiency and distal renal tubular acidosis. The probability  that an individual would inherit two recessive traits would be extremely low,  but inbreeding made that much more likely.

This wouldn’t seem to have much relevance here in the present, except as an  interesting side story in the history books. However, the authors note that  consanguineous marriages account for 20 to 50 percent of all unions in certain  populations in Asia and Africa and reach as high as 77.1 percent among army  families in Pakistan. In those families, more than 60 percent of marriages are  between first cousins.

Read more:  http://blogs.smithsonianmag.com/science/2009/04/royals-prove-inbreeding-is-a-bad-idea/#ixzz2TaIXYT4H