An unusual artery branch has increasingly appeared in the arms of modern adults, becoming three times more common in just over a century, providing evidence of ongoing evolution.
According to authors from the University of Adelaide and Flinders University, this artery branch exists in fetuses but gradually disappears as the fetus grows, becoming unseen in adults. However, that was the case a few centuries ago.
The blood vessels in the arms of many modern individuals are significantly different from those of previous centuries – (Illustrative image from Science Alert).
Scientists began to notice the existence of a strange accessory artery branch in the arms of some adults since the 18th century. A study on a population born in the 1880s showed that up to 10% of adults possessed this artery branch. New statistics from research on individuals born in the late 20th century indicate that the rate has increased to 30%, which is three times higher in just over a century.
The research was based on the remains of many Australian individuals of European descent who donated their bodies, aged between 51 and 101 at the time of death.
According to Science Alert, this artery branch, known as the “median artery”, typically regresses when the fetus is 8 weeks old, leaving the role to two other major blood vessels that we still see in adults: the radial artery and the ulnar artery.
Anatomist Teghan Lucas from Flinders University, a co-author of the study, stated that the prevalence of this artery branch is a manifestation of human evolution, as it indicates changes in certain genes that prevent this blood vessel from disappearing like in previous generations.
Individuals with this new evolutionary trait gain the advantage of more dexterous fingers and stronger arms due to increased blood supply; however, they also face a higher risk of developing carpal tunnel syndrome.
According to Dr. Lucas, if this evolutionary trend continues, by the year 2100, it will no longer be considered a rare trait since most people will possess it.
The study was recently published in the Journal of Anatomy.
