In the December 14th issue of the New York Times there was an article about a possible link between Neanderthals genes, who were early risers, and people in todays world who wake up early.
In the recent study, genetic material recovered from Neanderthal and Denisovans fossils was compared to DNA found in humans today. Interestingly, Neanderthals were shown to have shared several genetic variations associated to clocks with early risers. Hundreds of proteins interact with one another inside the cells of all animal species, rising and falling in a 24 hour cycle. They regulate not just our sleep and waking cycles but also our metabolism and hunger. In order to investigate the circadian rhythms of Denisovans and Neanderthals, Dr. Capra and his colleagues examined 246 genes involved in circadian regulation. They compared the gene variants found in extinct hominins with those found in living humans.
More than a thousand mutations that were exclusive to Neanderthals, Denisovans, or current humans were discovered by the researchers. Many of these mutations most likely had a significant impact on how the body clock functioned, according to their findings. For example, the researchers predicted that certain body clock proteins, which are common in human cells, would be less abundant in Neanderthal and Denisovans cells.
I found this interesting because it explains an interesting component of human evolution and how it might have influenced our current behavioral habits. The finding that modern humans sleep patterns may be influenced by Neanderthal genes linked to early awaking is important because it highlights the complexity of human evolution and how much interactions with other hominin species have impacted our genetic makeup. The study shows how important circadian rhythms are to human biology. Hormone production, metabolism, sleep and wake cycles, and other physiological activities are all significantly regulated by circadian rhythms. Through the finding of genetic variations associated with circadian rhythm in Denisovans and Neanderthals, scientists are able to gain a better understanding of the mechanisms that regulate these basic biological processes.