A new study suggests that human lineage has shifted to what we are today in a gradual manner. Researchers have said that the last common ancestor of humans and chimps were having shoulders akin to modern of African apes.

It is said that the human lineage has diverge chimpanzees around six million or 7 million years ago. As per the researchers, the ancestral state of the shoulders is quite vital to understand the human evolution as the shoulder is connected to important changes in the human lineage.

With the help of shoulder evolution, it can be find out when early humans started using tools and spent less time on trees and learned to throw weapons. In order to know how the shoulder of ancestral might have looked like, the researchers have developed 3D shoulder models from museum specimens of modern humans, chimps, bonobos, gorillas, orangutans, gibbons and monkeys.

The data was then compared with 3D models that other researchers have developed with regard to ancient, extinct relatives of modern humans, including Australopithecus afarensis, Australopithecus sediba, Homo ergaster and Neanderthals.

After comparing the data, the researchers came to know that the human shoulder has gradually evolved from an African apelike form to its modern state. “These results pretty much confirm that the simplest explanation for how the human shoulder evolved is the most likely one”, said the researchers.