Some of the "missing" human muscles over 250 million years ago were found not in sports enthusiasts but in embryos in the first few months.
The team captured the specialty by using new technology to create high-resolution 3D images from embryos and fetuses during the first trimester of pregnancy.
They found that at 7 weeks gestation (when the fetus is the size of a blueberry), there are about 30 muscles in the hand. By week 13 (the size of a lemon), 10 of them were fused and the number of muscles dropped to 20. Some of them even disappeared during the transition from traits like reptiles. mammal.
"Previously, we understood more about the early development of fish, frogs, chickens and mice than humans, but these new techniques allow us to see human development in much more detail.
What's even more intriguing is that we have observed various muscles that have never been described during human prenatal development, and some of these muscles have been seen even in those 11.5-week-old fetus, very late for developing muscular dystrophy, " said Dr. Rui Diogo, from Howard University.
The team said it was possible to capture a detailed timetable for the appearance of these muscles, as well as their separation, consolidation or loss during embryonic growth and development.
The fused muscles are called limb muscles, which are formed during the early human development. It provides an interesting view of evolution. We often find ourselves becoming more and more complex, but some anatomical features streamline and become simpler.
"In fact it's a story about simplifying anatomy. Mostly muscle loss, bone loss. An adult actually has less muscle and bone in the body than an adult mouse." or an adult lizard , " said Dr. Diogo.