Decoding the evolution of human upright gait

New research in the journal Nature deciphers how the pelvis evolved, allowing humans to walk upright and give birth to babies with large brains.

Comparison of human and primate skeletons in Thomas Henry Huxley's work on the evolution of man, published in 1863. (Source: Alamy)

A study published in the journal Nature on August 27 pointed out key changes in the structure of the pelvis, which helped human ancestors adapt to walking upright on two legs and have the ability to give birth to children with large brains.

A team of scientists from Harvard University (USA) and the Max Planck Institute for Evolutionary Anthropology (Germany) compared the embryonic development of the pelvis in humans with that of primates such as chimpanzees, apes, as well as mice. The results showed that two important evolutionary steps occurred during the embryonic stage, related to the development of cartilage and bone in the pelvic bone.

The first step occurs around the seventh week of pregnancy. In many primates, the hip bone develops into a vertical cartilage bar, while in humans, this cartilage rotates 90 degrees, making the pelvis shorter and wider.

The second step occurs around the 24th week of pregnancy, when cartilage is gradually replaced by bone cells. In humans, some bone cells form later than in other species, helping to maintain the characteristic shape of the pelvis throughout growth.

These two changes create a wide bowl-shaped pelvis, which is suitable for walking on two legs, supporting internal organs and helping the gluteal muscles maintain balance during movement.

In addition to anatomical and histological analysis, the scientists identified five genes that control molecular signals involved in cartilage growth and bone formation in the pelvis, which are thought to be crucial in helping humans develop their characteristic pelvis.

“Everything from the base of the skull to the tips of the toes in modern humans has changed to accommodate upright walking,” said Dr Tracy Kivell, Max Planck Institute. “This study opens up a new approach to understanding this evolutionary process.”

According to the research team, this discovery not only helps decode the evolution of modern humans but can also be applied in analyzing the genes of ancestral fossils such as Denisovans, thereby shedding light on the process of human skeletal formation over millions of years.

Source: https://baoquocte.vn/giai-ma-tien-hoa-dang-di-thang-dung-cua-loai-nguoi-326081.html