Friday, October 26, 2007

It’s Genetic Not Hormonal

Sex differences in cognition and behavior tend to categorize the brain as masculine or feminine and this is often thought to involve hormones. A recent study in mice shows that some sex-linked genes do not need hormones to shape male or female behavior.

Jane Taylor of Yale University looked into the habit-forming behaviors for which gender differences have been noted. They experimented with the Sry, a testes determining gene found on the Y chromosome. Scientists knocked out the Sry in the male mice and added the Sry to the female mice which produce XX mice with male hormones.

Taylor trained the normal male and female mice, and the XX mice with male hormones, to poke their noses through holes to obtain a food pellet. After the mice had developed the habit to poke through the holes for food the researchers injected a chemical into the mice after they obtained a food pellet. The chemical made them sick. Normally the mice will quickly learn to avoid the food but will still eat the food if they have developed an automatic habit; this is often called “condition taste aversion”. In this study, the XX mice regardless of whether they produced male or female hormones continued the behavior of eating the food. The XY mice did not continue eating. Thus, sex difference must have something to do with genes and does not involve the production of sex hormones.

Neurobiologist Lawrence Cahill of the University of California, Irvine, says that the study "relates very well to established sex differences in the acquisition of addictive habits."
She uses the example that women progress from casual drug-taking to a drug habit faster than men do. In this study, Taylor states that women may be good at multitasking because they can form habits that allow them to do chores frequently without thinking which leaves their higher brain functions free to perform other tasks.

This study opens up research in other species in which behavior may be attributed to genes instead of hormones.

Posted By:
Nelina Bridge(5)

1 Comments:

At 11:28 PM, Blogger PWH said...

Knowing how genes and hormones work together to determine behavior can be really important. Adding in the issues of gender differences and addictiveness makes this a very interesting article. I'm curious to know what other behavior can be predicted by simple genetics, male/female or otherwise.

Posted by Jon Hicks (5)

 

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