Successin almost any field depends more on energy and drive than it does onintelligence. This explains why we have so many stupid leaders.
- Sloan Wilson
NewYork - Another blow to male self-esteem. Researchers say mothers alonemay pass on the genes which determine a child's intellectual power,while fathers impart those genes controlling more instinctual,"primitive" mental functions. An article in this week's New Scientistmagazine says studies in mice are revealing that "the mother's genescontribute more to the development of the 'thinking' or 'executive'centres of the brain, while paternal genes have a greater impact on thedevelopment of the 'emotional' limbic brain."
Ongoing research atEngland's Cambridge University is exploring what scientists call"imprinted" genes, and their role in reproduction and evolution. Imprinted genes differ from other genes in that their activation withinthe developing child depends upon the sex of the parent from which thegene came. "Some imprinted genes work only if they come from themother," the New Scientist article explains. "The same gene issilenced if it is inherited via the sperm rather than the egg."
Cambridgescientists stumbled upon this fact in 1984, during research that soughtto discover if mammals could grow into maturity when supplied with thegenes of just one parent. But they found such "androgenetic (mouse)embryos died, because certain vital genes had been switched off by the(donor) father." Delving deeper into this phenomenon, researchersrealised that certain genes controlling the development of theconscious, "higher" level of brain function - intelligence - aresilenced in the paternal version, but operative in the maternal one. Conversely, genes controlling more primitive limbic function -emotions, and the drives to eat, copulate, and compete - are silencedin the mother's genes, but activated in the father's.
In anotherstudy, Cambridge researchers examined the brain development of mouseembryos, abnormally weighted with extra amounts of the genes of eitherone parent or the other. "As the embryos matured cells that carriedonly paternal genes accumulated in clusters scattered throughout the'emotional' brain - the hypothalamus, the amygdala," New Scientistreports. In embryos with maternally supplied genetic material, "cellscontaining only maternal genes were absent from the emotional brain. Instead, they selectively accumulated in the brain's executive region(the seat of higher, cognitive intelligence)."
Of course mice andmen do differ. "It is very important work, and very, very promising,"says Wolf Reik, who is studying the "imprinting" phenomenon at theBabraham Institute, near Cambridge. However, he admits that, at thisstage "everyone is a little bit lost as to what it really means." Butsome psychologists are already trumpeting the discoveries asvindication of Freudian theory. Christopher Badcock, author ofPsychoDarwinism, believes paternal genes help build Freud's famous "id"- the instinctual, emotional, unconscious self-while the mother's genesare behind the more rational, conscious "ego". During development,"maternal and paternal genes compete for control of behaviour," Badcockwrites, "culminating in a mind divided into two conflicting partsstrikingly similar to Freud's ego and id."
Whatever thepsychological implications, experts believe "imprint" genes (of whichonly three or four have been identified so far) may number in thehundreds or thousands. Improperly switched on or off, they could alsobe the cause of numerous genetically inherited diseases. Researcherssay more research may lead to ways of controlling the expression ofsuch genes - and reversing the progress of these conditions.
Source: Reuters Friday 26 May 1998 from New Scientist 3 May 1997 pages 34 - 39