A Patchwork Mind: How Your Parents' Genes Shape Your Brain

• When passing on DNA to their offspring, mothers silence certain genes, and fathers silence others. These imprinted genes usually result in a balanced, healthy brain, but when the process goes awry, neurological disorders can result.
• Imprinting errors are responsible for rare disorders such as Angelman and Prader-Willi syndromes, and some scientists are beginning to think imprinting might be implicated in more common illnesses such as autism and schizophrenia.
• Even typical brains are the result of asymmetric contributions from Mom and Dad. Higher cognitive function seems to be disproportionately controlled by Mom’s genes, whereas the drive to eat and mate is influenced by Dad’s.

It is true that children inherit 23 chromosomes from their mother and 23 complementary chromosomes from their father. But it turns out that genes from Mom and Dad do not always exert the same level of influence on the developing fetus. Sometimes it matters which parent you inherit a gene from—the genes in these cases, called imprinted genes because they carry an extra molecule like a stamp, add a whole new level of complexity to Mendelian inheritance. These molecular imprints silence genes; certain imprinted genes are silenced by the mother, whereas others are silenced by the father, and the result is the delicate balance of gene activation that usually produces a healthy baby.