We often learn about human evolution as something that happened. But who said that evolution is a completed process? That is not at all true – evolution is still happening and it will never be completed. However, our civilization removed some of the key factors for evolutions, such as hunting or farming for survival. But now scientists from University of Queensland found that natural selection in people still works.
Evolution is driven by the environment. Humans, as other animals, evolved to be fitting in their environment. We became smart hunters, learned to make and use tools, gathered up in social communities – all of this helped us to survive and thrive. However, now your skills do not matter that much and we choose our partners for raising children differently. So it would be easy to think that evolution has stopped or at least slowed down, especially in terms of natural selection. However, scientists developed a statistical method to examine the effect of DNA mutations on genetic architecture and found clear signatures of natural selection.
Natural selection means that traits that help to survive will be passed on to offspring. In other words, genes that make people more fit for their environment get passed on, while mutations that have negative implications for survival are less likely to be passed on to children – scientists call this “negative selection”. Scientists found evidence of negative selection in humans. For example, waist-to-hip ratio. Excess fat around the waist area is associated with cardiovascular disease and so these genes that promote unhealthy waist-to-hip ratio rarely get passed on. Furthermore, human reproductive system is also affected by the negative selection.
Negative selection protects human population from the spread of unwanted traits. Dr Jian Zeng, one of the leaders of the study, said: “Negative selection prevents ‘bad’ mutations from spreading through the population, meaning that common DNA variants are likely to have small or no effect on traits”. This study shows that human evolution is still happening and could be useful to predict where it is leading.
Humans can be arrogant sometimes. Evolution is still very much at work and it will always be. Understanding how it is happening at the moment may help us predict the future and see the implications of our lifestyle.
Source: University of Queensland