A new study has shown that Homo sapiens have not yet completed the evolutionary process.
An investigation by researchers at the University of Adelaide found that our forearms contain convincing evidence that we are still evolving, albeit on a small scale, because the prevalence of a blood vessel called the median artery has increased significantly since the late 19th century.
During the embryonic stage of our development, the median artery is the main vessel that carries blood to the forearm and hand.
In the past, the median artery has disappeared as the radial and ulnar arteries replace it while a baby is still developing in the womb, being an unusual feature in the adult forearm.
The researchers’ findings show that not only that the median artery no longer disappears in the case of some individuals, but also that these people represent a growing group.
What does this mean for evolution?
The study estimates that about one in three people maintain this median artery, but expects the trend to continue and the median artery to become more common as a permanent feature of the human forearm.
When it is found that over 50% of people have an “abnormality”, it will cease to be abnormal and will become the new norm for human anatomy.
Researchers have called this change “microevolution,” because while modern humans are evolving at a faster pace than at any stage in the last 250 years, this change is small.
“Since the 18th century, anatomists have been studying the prevalence of this artery in adults, and our study shows that it is clearly growing,” said Dr. Teghan Lucas, the study’s author.
“The prevalence was about 10% in people born in the mid-1880s, compared to 30% in those born in the late twentieth century, so this is a significant increase in a fairly short period of time, when it comes to of evolution.
This increase could have resulted from mutations in the genes involved in the development of the median artery or health problems in mothers during pregnancy. If this trend continues, most people will have a median forearm artery by 2100. ”
Researchers believe it is a beneficial anatomical feature because it increases the total blood supply to the forearm and hand.
It is hoped that it could be used even during surgery as a replacement for damaged vessels in other parts of the body.
According to the researchers, this arterial microevolution joins other examples that demonstrate how human anatomy changes over time, including abnormal leg connections, the growing absence of mental masses, and the growing presence of a small bone behind the knee joint.