Like a Virgin by Prasad Aarathi

Author:Prasad, Aarathi [Prasad, Aarathi]
Language: eng
Format: epub
ISBN: 9781780740676
Publisher: Oneworld Publications (trade)
Published: 2012-08-22T18:30:00+00:00

Bizarrely, because of how imprinting works, a father also sways his child’s life after birth, through the timed influence of his genes. Some of a father’s genes, in fact, only become expressed after a baby has been weaned, and they can have a significant effect at much later stages of life. For instance, the father’s genes have a say in whether or not a child develops disorders related to food, possibly including obesity. Here, once again, we see the battle between the father’s DNA and the mother’s body.

This is because those eighty genes that are subject to imprinting have an important say in the development of our brains. Those genes that are silenced when inherited from the mother but expressed when inherited from the father inhibit our overall brain size; they contribute to the development of the hypothalamus – the impulse centre that makes us crave food. In contrast, the imprinted genes that are expressed when inherited from the mother contribute to the cortex, the so-called grey matter of higher mental functions; the striatum, which is involved in decision-making and risk-taking; and the hippocampus, the brain’s memory centre. Recent molecular analysis has shown that among people who carry defects or mutations in genes that are supposed to be imprinted, there is a surprisingly large incidence of cognitive, behavioural, neurological, and psychiatric conditions. These include autism, bipolar affective disorder, epilepsy, schizophrenia, and Tourette’s syndrome.

This sex divide in the role of imprinted genes on the brain is curious, because what happens in the hypothalamus is also believed to influence maternal behaviour. Studies in mice have shown that mothers will neglect their offspring if the PEG1 gene (paternally expressed gene 1) is removed from their fathers so that they are not able to inherit it. A related gene, called PEG3, increases maternal care, too, and also regulates male sexual behaviour – meaning it ensures its own preservation. If a male mouse does not have the PEG3 gene, then, no matter how much sexual experience it gains, it is unable to improve its reproductive effectiveness; for example, no amount of experience will make the mouse better able to recognize the odours that female mice secrete when they are ready to mate. It seems that a father can even directly influence how his daughter will behave towards her own children, through imprinted genes alone.

For mice and men (and women), evolution has pitched mother against father, father against mother, mother against child, and child against mother – our genetic sources and our genetic creations are all battling for control. The outcome of these long-ago skirmishes is a treaty written in DNA: neither a mother nor a father may use all the genes at their disposal, but both will have a genetic and a chemical voice that will continue whispering into the brains of their children – all the way into adulthood. Neither sex can do without the other. At least, that is, while we are still constrained by the body.

But what comes next? Will those restrictions

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