Using a combination of artificial intelligence and genome-wide association studies, the researchers created the first map of genomic regions responsible for skeletal changes in primates that led to upright posture, reports Europa Press.
Thus, the map shows that the genes underlying the anatomical changes observed in the fossil record were strongly influenced by natural selection and gave early humans an evolutionary advantage.
“On a more practical level, we have also identified genetic variants and skeletal features associated with arthritis of the hip, knee, and back, which are the leading causes of disability in adults in the United States,” said Tarjinder Singh, co-leader of the study and associate professor in the Department of Computational Genomics and Statistics at Columbia University.
Similarly, it showed that small deviations from the mean hip width-to-height ratio were associated with an increased risk of hip osteoarthritis, while small deviations from the tibiofemoral angle were associated with an increased risk of knee osteoarthritis.
The data is helping researchers develop new ways to prevent and treat these debilitating diseases, the study says.
The researchers used deep learning to analyze more than 30,000 whole-body X-rays from the British Biobank, an institution that holds biological samples linked to clinical information.
They then scanned the human genome to identify chromosomal regions associated with variations in 23 key skeletal measurements, including shoulder width, torso length, and tibial angle.
This process identified 145 regions associated with genes that regulate skeletal development.
Many of these coincided with “accelerated” regions of the human genome that evolved rapidly over millennia compared to the same regions in great apes.
In contrast, several genes associated with the heart, immune system, metabolism, and other traits have been found in the accelerated regions.
“What we are seeing is the first genomic evidence that selective pressures were applied to genetic variants that affect skeletal proportions, allowing the shift from a knuckle-based gait to an upright posture,” says Dr. Vagish M. Narasimhan, assistant professor of integrative biology, statistics, and information sciences at the University of Texas and co-lead of the paper.
Scientists specified that the most profound progress in the evolution of primates occurred about 6 million years ago, when our ancestors began to walk on two legs; and the gradual transition to bipedal locomotion is thought to have made primates more adaptable to different environments, allowing them to free their hands to use tools, leading to accelerated cognitive development, paving the way for modern humans.