Science Scoops: Black Cats Have Good Luck!
by Stephen James O'Meara
The next time a black cat crosses your path, don't panic. Instead, think about the recent research by Stephen O'Brien and Eduardo Eizirik, evolutionary geneticists at the U.S. National Cancer Institute in Maryland. If the researchers are right, dark fur has a survival benefit.
Here's the scoop. The research began with a simple question: What makes a cat black? The scientists weren't passing time. They had a gut feeling that the genes involved in making a cat's coat turn black may also protect the animal against disease.
Well, O'Brien's team did find the gene (called MC1R) that, when mutated, makes a cat's coat turn black. In fact, O'Brien and his team said that they found that the black domestic cat, the jaguar, and the small South American jaguarundi each derive their black coloring from a different type of gene mutation.
MC1R is in a family of genes called 7-transmembrane receptors. A receptor acts as a doorway into cells and is often used by bacteria and viruses to infect cells. The HIV virus, for instance, enters cells through a 7-transmembrane receptor.
So, the genes that give a cat its black coat are in the same gene family as those involved in acquiring human diseases like AIDS. Black cats with the mutated gene may be more resistant to disease than cats of other colors. Learning more about this gene might help in human disease research.
The discovery casts a new light on animals that at one point were even tortured by people who saw them as agents of the devil. “We have had black cats and they have been mythical all along,” O'Brien says, “but now they have been demystified.”
- mutation: Any change in a genome or a chromosome.
- Mutations can be harmful or helpful. There are genetic mutations that cause disorders, such as sickle-cell anemia or certain cancers. How might the mutation described in this article be beneficial to a cat?
[anno: The mutated gene that causes a cat's fur to be black may also help protect the cat against certain diseases and viruses.]
- If some mutations are beneficial and others are harmful, what might be the reason that genes mutate? What could be the benefit to a species of particular gene mutations? Write a paragraph explaining why genetic mutations might be beneficial to a species.
[anno: Answers will vary but could include opinions that certain genetic mutations help protect a species and may increase a species' chances of survival.]