A genetic change in human ancestors may partly explain why humans don’t have a tail, suggests a study released today that is on the cover of scientific magazine Nature.
The study, led by scientists from New York University Grossman School of Medicinein the United States, compared the DNA (genetic code) of tailless apes (such as gorillas, chimpanzees and orangutans) and the DNA of humans with the DNA of tailed monkeys and revealed a DNA insert shared by apes and humans, but absent in monkeys.
In the laboratory, the team genetically manipulated mice to check whether insertion into a gene called TBXT it affected their tails, and detected several effects, with some rodents being born without tails.
Scientists maintain that the differences in tail lengths found did not arise from mutations in the TBXT gene, but from insertion of a DNA fragment called AluY into the gene regulatory code in the ancestors of apes and humanssays New York University in a statement.
The note highlights that genes often influence more than one function in the body, so “changes that bring an advantage in one place may be harmful in another”.
Increase in neural tube defects
The study authors detected a small increase in neural tube defects (the embryonic structure that will give rise to the brain and spinal cord) in genetically manipulated mice.
In future experiments, the team wants to test the theory that, in an “ancient evolutionary compensation”, tail loss in humans contributed to neural tube birth defects, such as spina bifida, currently observed in “one in every thousand human neonates “.
2024-03-03 10:00:37
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