Brain complexity: finding the genetic cause (Introduction)

by David Turell , Saturday, August 29, 2015, 14:45 (3153 days ago) @ David Turell

A control of alternate splicing in genetic modification causes neurons to proliferate:-http://www.sciencedaily.com/releases/2015/08/150820144840.htm-"A single molecular event in our cells could hold the key to how we evolved to become the smartest animal on the planet, scientists report. They have uncovered how a small change in a protein called PTBP1 can spur the creation of neurons -- cells that make the brain -- that could have fuelled the evolution of mammalian brains to become the largest and most complex among vertebrates. -***-"The key lays in the process that Blencowe's group studies, known as alternative splicing (AS), whereby gene products are assembled into proteins, which are the building blocks of life. During AS, gene fragments -- called exons -- are shuffled to make different protein shapes. It's like LEGO, where some fragments can be missing from the final protein shape.-***-"Gueroussov previously helped identify PTBP1 as a protein that takes on another form in mammals, in addition to the one common to all vertebrates. The second form of mammalian PTBP1 is shorter because a small fragment is omitted during AS and does not make it into the final protein shape.-"Could this newly acquired, mammalian version of PTBP1 give clues to how our brains evolved?-"PTBP1 is both a target and major regulator of AS. PTBP1's job in a cell is to stop it from becoming a neuron by holding off AS of hundreds of other gene products.-"Gueroussov showed that in mammalian cells, the presence of the second, shorter version of PTBP1 unleashes a cascade of AS events, tipping the scales of protein balance so that a cell becomes a neuron."-Comment: My chicken and egg reasoning: Just because neurons are made in larger number does not create the complex arrangement of a brain. So many more very necessary and specific steps are needed to get humans. Still smells like teleology to me.