Peoples around the world evolved pygmy traits to adapt better while living in the rainforest, researchers said this week in a new study.
A smaller body size appears to have developed independently in Central Africa, Southeast Asia and other rainforest areas to help these people groups survive, Live Science reported.
Publishing their research in the Proceedings of the National Academy of Sciences of the United States of America, the scientists analyzed the genomes of the Batwa people in the east Central African rainforest and the Baka in the west.
"We have found the strongest evidence yet that the pygmy phenotype is controlled by genetics," said researcher Luis Barreiro of the University of Montreal, as quoted by National Geographic.
Batwa men have an average height of 60.1 inches, while women stand at 57.4 inches on average; their heights are significantly lower than average statures in nearby Bakiga, where the average man is 65.1 inches tall and the average woman 61 inches.
The research team surveyed 169 pygmy people of Batwa to compare their genomes to 61 Bakiga people, discovering that the Batwa people carried genetic variations connected with stature and growth hormone.
The scientists' hypothesis is that smaller body sizes evolved partly because they require fewer calories for survival. Smaller people will also generate less body heat during activity, making it easier for them to be cooled down by sweat in the humid rainforest environment.
For future investigations, researchers hope to study more Southeast Asia people groups to learn more about how height evolved in different areas.
"In addition, I would like to expand these studies to rainforest hunter-gatherer populations in Southeast Asia, in order to study the extent to which any such adaptations like height have also evolved convergently across continents," said lead study author George Perry, an anthropologist at Pennsylvania State University in University Park, as quoted by Live Science.
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