While humans have made many notable strides in evolutionary
differences between our fellow mammals – opposable thumbs, brain size and
development, advanced language, etc – one notable stride has been gaining the
attention of evolutionary biologists, neurologists, anthropologists, and geneticists
alike. The expansion and exploration of humanity has fallen under the
microscope and the research in this area is ever-growing. As reported by none
other than National Geographic (who better?), multiple fields of scientists are examining human exploration,
including geneticists. In recent studies, geneticists have been examining the
effects of a variation on the DRD4
gene, a gene which influences dopamine, an important neurotransmitter
in regards to learning, rewards, excitement, and pleasure. The variant in question,
DRD4-7R, has been linked to Attention Deficit Hyperactivity Disorder
(ADHD), and is starting to get linked to the exploratory tendency of human
nature. In a broad sense, human studies have correlated the presence of the 7R
variation to restlessness, curiosity, and higher inclination towards adventure
and change. In a larger study conducted by
the University of California, the variant 7R was found more commonly in individuals
whose ancestors were highly migratory than those who hailed from more sedentary
populations. Other studies have found R7 to be more common in individuals whose
ancestors had longer tracks of migration, individuals in modern-day migratory
groups who are more physically fit and well-nourished when migrating often as
opposed to poorly-nourished individuals in settled villages, and even more
common in individuals who have lived to old age and exercised well during their
lifetime (both in humans and mice) .
While multiple studies do come to the conclusion that there is a correlation of
the variant in individuals whose ancestors travel and who benefit well from
enriching environments and movement in their lifetime, most professionals agree
that human exploration, while unique even among hominids (not even Neanderthals
were known to move far from their established territories) , cannot be placed
solely onto a single gene. Humans are the only mammal known to explore beyond
established territories without the need to do so (i.e. depleted resources, following
prey, etc.), but there have been a lot of physical adaptations that have led to
this unique trend. The change from quadrupedal to bipedal movement allowed
humans to expand their territorial range and increase their endurance; the
expansion of the brain and the delay in maturation has allowed for the increase
in creative thinking as well as intellect that lead to innovative tools and
understanding of scenario-based potential outcomes; the rather un-matched
dexterity of human hands allowed the human imagination to expand and build
tools to aid in travel. While the R7 gene may correlate to hyperactivity and
perhaps to the urge to move and maybe even travel, there are many factors that
have led to the expansion and exploration that is inherent in humanity.
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