What Do Genes Do?[I], [XVII], [XVIII]

One way researchers probe a gene’s operations is by altering it in lab animals. They substitute DNA segments in mouse embryos to create knock-out mice where the gene no longer functions, then observe differences from normal mice. They can also enhance the activity of a gene to create knock-in mice. Researchers use genetically engineered animals and cells as tools to investigate normal brain functions and disease processes at the molecular level. For example, to explore the role of a cytokine (a chemical linked to the inflammatory response) in memory, investigators measured memory in mice bred to lack a receptor for the cytokine, or to produce a chemical that blocked it. Drug researchers similarly used knock-out and knock-in mice to identify a brain receptor that is crucial to the response to nicotine, and to show how genetic variations might explain in part why some people become addicted to cigarettes and others don’t.  

Pharmacogenetics[II], [XIX], [XX]

Genetics researchers probe interactions between genes and drugs to work toward the goal of personalized medicine—tailoring treatment to the individual—and insights that could lead to new drug development. In this effort, researchers have analyzed whole genome-association studies in search of markers to identify people with major depression who are likely to get better with fewer side effects when given specific antidepressants. In addition, researchers enlist studies using genetically engineered animals to map the molecular pathways that determine response to these medications and advance research into more effective ones.

THE GENETICS OF GENIUS

David T. Lykken

Psychologists once thought, simplistically, that genius was nothing more than high general intelligence, the capacity measured by the intelligence quotient or IQ. IQ scores of 140 and above, attained by perhaps four in every thousand youngsters, were classified as in the ´genius range.' Stanford University's Lewis Terman, who was responsible for revising and standardizing the first individually-administered IQ test, the Stanford-Binet, identified some 1500 gifted children with IQs in this range and Terman's gifted group have now been followed through middle age. Most of them have led relatively successful lives but none of them, so far as I am aware, would be classified as geniuses today.

At the other end of the IQ scale, a rare few of retarded or autistic persons, known as savants, can quickly specify the day of the week on which any date in history fell or, although unable to read music, can play on the piano any composition after just a single hearing. These highly specialized abilities seem all the more remarkable in people whose general intelligence may be so low that they are dependent on others for their care and sustenance. Autistic savants are not geniuses either, of course, but these remarkable people seem to me to illustrate an important fact about the structure of mind.

It is meaningless to ask whether Isaac Newton's genius was due more to his genes or his environment, as meaningless as asking whether the area of a rectangle is due more to its length or its width. But if a certain group of rectangles vary in width between 1 and 10 inches but vary in length from 1 to 100 inches, then we can say, for the group, that the variation in their areas is more affected by the variation in their lengths than by the lesser variation in their widths.[4] Similarly, for people in general, it is meaningful to ask whether their genetic differences are more or less important than their differences in experience in producing the variation we observe in the traits involved in genius. The proportion of the total variation in any trait that is associated with genetic variation is called the heritability of that trait.

It is important to understand that the heritability of most psychological traits tells us as much about the given culture as it does about human nature. It is likely (although we cannot be sure of this) that the amount of genetic variability among people within each human culture or breeding group is about the same. But environmental opportunities vary widely both within and between cultures. We would not expect to find a literary genius in a preliterate tribe in Papua New Guinea. In the Middle Ages, peasant children had much less opportunity to develop their intellectual capacities than the children of princes and the heritability of IQ then would have been decreased by this large amount of environmental variation. On the other hand, the fact that the heritability of IQ among the citizens of modern western democracies is on the order of 75 per cent suggests that these cultures have succeeded in providing environmental opportunity that is tolerably equal for all their children (at least for their white children; we are less sure about the heritability of IQ among, e.g., African Americans, for whom the relevant environmental variation may be greater).

Is emotional intelligence a better indicator of brain health than IQ?

As workers try to advance through the corporate world, they often hear the old adage, "It's not what you know, it's who you know." Those who do manage to get ahead likely possess emotional intelligence, a measure of how well a person can regulate his or her own emotions, as well as the emotions of other people. Emotional intelligence includes attributes such as empathy and emotional control. The term "emotional intelligence" became famous when it served as the title of Daniel Goleman's 1995 book; the book featured a scintillating subtitle that promised to explain "why [emotional intelligence] can matter more than IQ." An IQ score, a number comprised of verbal, mathematical, mechanical and memory ability, can seem like the holy grail for intelligence, and it can remain an excellent predictor of how well a person will do in school. Yet Goleman's book served up examples of how poorly an IQ score can predict a person's earning power or eventual success and happiness in life. For that, Goleman argued, you had to turn to emotional intelligence and a person's ability to use his or her emotions to navigate the world. While IQ scores rely on a person's ability to identify one correct answer, life sometimes involves more than one right answer, as well as the ability to get along with more than one type of person.

How Male and Female Brains Differ