Planet of the Brains

The difference between humans and other animals is often thought to be our complex thinking skills, introspection, and other advanced thinking processes. The advanced development of the human brain is our biggest asset and what we can thank for the success of our species. Our brain development is one of the things that separates us from other animals like apes. But why are humans so lucky to have this biological advantage? One of the things we can thank are neural progenitors, a special type of stem cell used in the early stages of brain development. Although neural progenitors are found in other animals like apes, the rate at which these neural progenitors multiply is different. This is essential because this rate can determine brain development. These cells start off in a cylindrical shape which allows for easy division into identical daughter cells but as the cells age they stretch to a longer shape. This process of multiplication and elongation is different in every animal; for example in chimpanzees this takes five days but in humans this takes about seven days. Since this process takes longer in humans more neural progenitors multiply by splitting into daughter cells, so more neurons are created later. Scientists compared the genes of gorillas and humans by turning genes off and on in a simulator and discovered a gene responsible for this process. The gene ZEB2 is responsible for the difference in multiplication and elongation of the neural progenitors. Scientists began to run more experiments and found that turning off the ZEB2 gene sooner in a human model caused the brain to develop more similarly to an ape. While if turned on earlier in the ape model the brain develops more similarly to a human. Although they become more similar to each other opposite there are many other factors that contribute to the differences in brains.

Moreover, This isn’t the only gene responsible for humans’ biggest asset. Other reasons for our brains’ great capability is the major increase in size due to the evolution of neurons, a great increase in these have given the human species an advantage. A different gene called Notch2NL was discovered and these are found only in the human genome. This gene expands human cortical cells and this gives humans more neurons. This surplus of neurons allows information to be relayed quicker between different areas of the brain and nervous system, being one of the reasons humans have more developed brains compared to other animals.

This new information supports the idea of evolution today because this supports the idea that humans and apes share a common ancestor due to the fact some genes are shared. On the other hand, there are genes found only in humans like the Notch2Nl gene and other genes like the ZEB2 perform differently in humans and apes. This difference in genes supports the idea that humans broke off from apes millions of years ago and evolved separately giving us different features from other animals. Overall, this new information gave us a better understanding of how the human brain works differently from other animals and even more proof of evolution.

About Mr. Mohn

Biology Teacher

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