Human and chimpanzee genomes are 99% identical. So why do humans, on average, live more than 40 years longer?
The average lifespan of a male human is 76 years while the average lifespan of a male chimpanzee is 31 years. Humans actually began living longer about 3.4-2.5 million years ago when they became meat eaters. It is thought that meat provided abundant calories and proteins for brain growth, but also exposed humans to many pathogens, since cooking was only invented 1 million years ago. Human and chimpanzee genomes are 99% identical and the uniquely human 1% possesses a high number of genes important in host defense and immunity necessary for initiation of the inflammatory response. Humans have a unique apolipoprotein E (APOE) gene important in the transport and metabolism of lipids different from chimps. APOE e4 ramps up in the acute phase of inflammation increasing IL6 and inducing fever and fighting off microbe replication. Thus, it is the human immune system that confers longevity.
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