Human uniqueness: genome interactions with environment, behaviour and culture

Abstract

'Anthropogeny' (explaining the origin of humans) requires a transdisciplinary approach that eschews disciplinary barriers and rejects artificial 'genes versus environment' dichotomies. The genomic and genetic approach towards this goal is made quite difficult by the discovery of much greater molecular variation than originally expected, both within and between species. As only a few simple molecular differences have been identified that might underlie human uniqueness, both traditional and novel approaches are needed to understand the genetic aspects of human evolution. It is fruitless to argue over whether differences in gene expression, in protein and RNA sequence variation, or in genomic deletions, duplications and insertions are more important in exploring human uniqueness. Examples of each have been found, and it is likely that final answers will involve many more in each category. Integrated molecular studies along with parallel organ-systems approaches are required to identify and characterize candidate genes. Genome interactions with environment, behaviour and culture are likely to be more prominent in humans than in other species. Aspects of human uniqueness might have arisen because of a primate evolutionary trend towards increasing and irreversible dependence on learned behaviours and culture, rather than hard-wired instinctual behaviours. This, in turn, might have relaxed allowable thresholds for large-scale genomic structural variation in primates in general, and humans in particular. In addition to conventional Darwinian mechanisms, there are potential roles for the Baldwin effect; humans might have escaped the second phase of the Baldwin effect, wherein there is genetic hard-wiring of learned behaviour that is beneficial to a population. The unusual degree of exaptation of the human mind might require consideration of additional novel mechanisms, as originally suggested by Alfred Russel Wallace.