Neoteny in gene expression in human brain

In chapter 11 of my book I describe the process by which I believe humans domesticated themselves, compared to chimpanzees. The principle idea evokes a process called neoteny, first described by Ashley Montagu and Steven J Gould, which involves so-called heterochronic shifts in the timing of development from foetus to adult - a staggering or delaying of the developmental clock such that important stages in development get prolonged and delayed. For e.g. childhood and adolescence. Corresponding changes in body, skull and jaw morphology are noticed as a result of neoteny, which might explain Homo sapiens' more gracile morphology. Although neoteny has been reported in the pattern of switching on of flows of adeno-corticoseroid stress hormones and some brain neurotransmitters, this concept has not been applied to gene expression - the timing of active protein production in genes. Now a research group including Philipp Khaitovich and Svante Paabo has reported just such a study, documenting a startling number of genes exhibiting delays in their protein-producing activity unique to humans. These genes are all active in the pre-frontal cortex, evolutionarily the most recent, and advanced, part of the human brain and seem mainly concerned with growth and development of grey matter. "There is a human specific neotenic shift in gene expression during postnatal maturation of the human prefrontal cortex, causing adult humans to resemble juvenile chimpanzees in their expression profiles." Importantly, they point out, the period when this delayed gene expression finally kicks in corresponds to the period of dramatic re-sculpting of synapse connections in the brain which we associate with late adolescence and early adult maturity - when the pefrontal cortex is finally taking on its adult organization. "Delayed grey-matter maturation in the human prefrontal cortex may extend the period of neuronal plasticity associated with active larning, thus providing humans with additional time to acquire knowledge and skills". As the father of a late-teen son, I sincerely hope they are right!!