Molecular biology concerns human evolution

To gain a clearer picture of health and disease, scientists have now provided an independent reference for all human variation by looking through the evolutionary lens of our nearest relatives.

            By observing evolution's "greatest hits" (and misses) and the history of the major themes and patterns of genome conservation (and divergence) across many species, scientists can predict probable mutations that will be found among people and the fate of human variation.

            The research team relied on an evolutionary tree that included 46 vertebrate species spanning over 500 million years of life on Earth to predict the evolutionary probability (EP) of each possibility at each position of our genome. They applied their new method on all protein-coding genes in the human genome (more than 10 million positions). Consistent with the knowledge that most mutations are harmful, they found very low EPs (lower than 0.05) for a vast majority of potential mutations (94.4 percent).

            Next, they produced a complete evolutionary catalog of all human protein variation, or evolutionary variome, that can be used to better understand human diseases and adaptations. And, it can be directly applied to the genomes of any other species.

            We think that the fascinating part of the story is that once we know what our ancient evolutionary history predicts, then we can compare this expectation to what we observe in human populations today.

Read more at: http://www.sciencedaily.com/releases/2015/10/151029124542.htm

DNA reveals mysterious human cousin with huge teeth

A new genetic analysis suggests that the recently discovered Denisovans lived in Eurasia for millennia.

            The analysis of a fossil tooth from Siberia reveals that a mysterious people known as Denisovans, discovered a mere five years ago, persisted for tens of thousands of years alongside modern humans and Neanderthals.

            The find underscores that our Homo sapiens ancestors shared the Eurasian continent with other human-like populations. So this new study marks an important step in scientists’ understanding of where Denisovans fit in the human family tree.

            In 2010, teams of geneticists and anthropologists announced strange DNA sequences recovered from a finger bone and molar found in the remote Denisova cave, in Siberia’s Altai Mountains.

            The DNA shows that Denisovans left their mark on modern humans, contributing about five percent of the genome of modern Melanesians, who live in Papua New Guinea and other parts of the Pacific.

                The teeth found in the cave were bigger and stronger than the ones known from Neanderthals and humans. Although it is difficult to say what large-toothed Denisovans would have looked like but it is almost clear that those large teeth with massive roots would probably require massive jaws.

                This is a very important research, because it reveals that human modern genome is composed (even if it is only a 5%) of Denisonvan DNA. Besides, it can change the way we think about the human family tree. 

Read more at: http://news.nationalgeographic.com/2015/11/151116-denisovan-human-anthropology-ancient-dna/