Researchers in Australia have discovered evidence of microevolution in humans, proving we’re still evolving in unique but subtle ways.
Research, published in the Journal of Anatomy, looked at the prevalence of the median artery in adults to find evidence for microevolution in modern humans.
The median artery is the main blood supply of the forearm and hands during embryonic development. By the eighth week of intrauterine life, it disappears and is replaced by radial and ulnar arteries. However, the prevalence of the median artery has been increasing in adults since the 18th century.
Limbs Dissected for the Presence of Median Artery
Researchers from Flinders University and the University of Adelaide aimed to investigate the prevalence over the last 250 years. To analyze the prevalence, they dissected 78 upper limbs from donors between the ages of 51 to 101 years. They compared their figures with those from previous studies.
The prevalence was around 10 percent in people born in the mid-1880s compared to 30 percent in those born in the late 20th century, so that’s a significant increase in a fairly short period of time when it comes to evolution.
Dr. Teghan Lucas, anatomist at Flinders University
The prevalence stands at 35% at the moment. Once it reaches 50% it will become a normal human structure and stop being a variant.
Microevolution – What are the Signs?
The study found the prevalence increased three times more than what it was 100 years ago. Thus, providing evidence for microevolution in modern humans.
This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually. If this trend continues, a majority of people will have median artery of the forearm by 2100.
Dr. Teghan Lucas, anatomist at Flinders University
According to Professor Maciej Henneberg, the median artery is the perfect example of microevolution due to the significant increase in its prevalence.
However, the median artery is not the only anatomical evidence of humans changing. Other examples include an increase in the absence of wisdom teeth and abnormal connections between the bones in the feet.
The increased prevalence of the median artery can end up benefitting humans as it increases the overall blood supply. Thus, ultimately assisting in the replacement of damaged blood vessels in other parts of the body.
It would be interesting to discover how these anatomical changes might differ across continents.
Reference:
Lucas, T., Kumaratilake, J., & Henneberg, M. (2020). Recently increased prevalence of the human median artery of the forearm: A microevolutionary change. Journal of Anatomy. doi:10.1111/joa.13224
