We have further derived this analyses to an important biological problem. That is new gene evolution detected by genomic computation, which we find that actually new genes can serve as driver for evolution of human brain. We know that today we human beings have a big brain. We also know that this big brain evolved not long time ago from ancestor which is with a smaller brain. During the evolution of brain size, our ancestor created a foraging tool indicates origin of intelligence. Our ancestor also introduced fire, which is a great event. And our ancestor also created a concept by painting, drawing in the rock. Those show that our ancestor had the ability to derive a concept with growing such a brain. Most exciting today we human beings know where we are from. And also we know what the universe , the planet. So this observation immediately asks a question. What genetic changes occurred in our ancestors drove evolution of brain intelligence? Right now we analyze if new genes play a role in brain evolution. Using a similar pipeline I just introduced in last section, we identify the new genes in a group of vertebrate species using the principle as we showed ??? everywhere gene A is the old gene. Gene B only appears in four species, so we know that B originated in this time.Origin of the gene B And if human beings only have gene E, then the single gene only appear of human being divergent functional pattern from all the rest of genome. C, D, F are very old. Use that bioinformatic analyses , we identify the new genes which originated in various evolution time shown in this red line which evolve toward human lineage. In total, we identified more than 5500 genes which are mammal-specific; among them there are about 1800 genes which are primate-specific. among them there are about 1800 genes which are primate-specific. So average rate of gene origination in vertebrate is about 20 genes per million years, which entered the genome of our ancestor. And in the primate species, then 30 genes originated per million years to enter the primate ancestor of human beings. In our human specific lineage, we have highest origination rate which is fixed about 80 genes per million years. Look at the expression of these new genes using the recently created database of gene expression in different kinds of tissues in human and mouse. We identify that there is much higher proportion of new genes, which express in the brain of human being comparing to the mouse, while mouse have different types of genes control their biology in that distribution. Then we also compare expression level by comparing expression of parental genes. And we see that after the new gene created, most often their expression level becomes upregulation in the neocortex and prefrontal cortex as we identify their proportion. And the proportion increases as the evolution time approaches to today. A very exciting discovery is that, we see that first when we are looking at the distribution of those genes originated in different stages as shown in red color, And all the genes appear in different stages actually express in neocortex of human being. Surprisingly, they are not really express high abundant in adult brain. But they express in higher level in prefrontal cortex and temporal lobe of the baby or early development of human brain. So this suggested that new gene evolve in early development which will regulate expression of later genes which are involved in cognitive function. Here I give one example. A new gene in these 54 genes is human specific, called SRGAP2C evolved from SRGAP2 by partial duplication. Scientists express this gene in the mouse, and by comparing to wild type mouse which the mouse brain neuron looks like this, which contain a certain structure called spines which are involved in the connection between different neurons. And the new gene SRGAP2C after express, they observe that the spines have longer necks as we shown over there and also more spines involved this gene in the brain of the mouse. So this suggested that, with the expression of the new gene in mouse brain, it might help the neurons in the mouse brain have tighter connection. Therefore, it might enhance the computing power of the brain, implicated important function in human brain. So in this section, we introduced that evolution of brain was accompanied with origin of new genes. Then we also found that new genes are upregulated in the neocortex, in particular the prefrontal cortex regions, throughout evolution of vertebrates. And finally, we reported that many new genes, in particular human-specific new genes, expressed in the prefrontal cortex and temporal lobe of the brain structure of early development involved for cognitive functions. Thank you!
