Redheads are popular study subjects. Once again, scientists have found that redheads, carriers of a particular variant of the melanocortin-1 receptor gene (MC1R), appear more sensitive to pain and temperature than darker haired folk.
In a study that I would have to be paid good money to volunteer for, scientists attached heating elements (maybe something like curling irons?!) to the arms of 60 redheaded volunteers and 60 with dark hair to test their tolerance to temperature. Redheads started reporting pain from cold temperatures at 6°C higher than dark-haired subjects. Professor Daniel Sessler, director of the Outcomes Research Institute and department of anaesthesiology at Louisville University, believes that variations in the MC1R gene may over-activate temperature-detecting genes, thus making carriers more sensitive to thermal pain.
Other special characteristics of redheads (some anecdotal):
- Anaesthesia often fail or unusually high doses of local anaesthetics are required to achieve adequate analgesia in redheads.
- Redheads are more resistant to the effects of lidocaine, a common local anaesthetic.
- Redheads are more sensitive to ultraviolet light, which is why they burn more easily in the sun, and it predisposes them to skin cancer.
- Redheads have a fiery temper, which may have helped give them the aggression they needed to survive in the harsh northern climates.
Professor Ian Jackson, from the MRC Human Genetics Unit in Edinburgh, said:
Nearly half of the population in Scotland now carry the genes that code for red hair, so any disadvantage must be fairly mild or outweighed by its benefits.”
One of the benefits mentioned was that greater sensitivity to cold may have helped protect redheaded individuals in colder climates by making them seek shelter and wrap up against the elements before their dark-haired counterparts. I’m not sure I buy this person-as-thermometer explanation but I can’t come up with a better one right now.
Scotland on Sunday, September 11, 2005