Evolution never really stops, which is why we modern humans are still going through evolutionary changes.
Recently, some researchers have discovered evidence that is evident in human genes, demonstrating that our fertility and heart function are still changing over time.
Natural selection is not a massive and forceful process. It involves changes that are slow and last for generations. These changes are also so small and subtle that we hardly notice them. However, geneticists at the University of Queensland in Australia have found a way to detect these changes. They use statistical methods to find mutations in DNA.
Scientists Jian Yang, Jian Zeng and a team of other researchers from the university’s Institute of Molecular Biology and the Queensland Brain Institute studied the genetic data of 126,545 individuals at the British Biobank – here is an anonymous UK health database. The researchers thoroughly examined 28 complex characteristics, such as heel bone mineral density, male pattern baldness, BMI, age at menopause and first menarche in women, and age of women giving birth for the first time, grip strength and hip-waist ratio.
Modern humans are still evolving. (Photo: iStock).
By studying the genes associated with these traits in individuals of different ages, scientists can see generational differences.
“During natural selection, or ‘survival of the best fit’, traits that are likely to improve human survival are more likely to be passed on to the next generation. The reverse also occurs, DNA mutations that adversely affect the most suitable individuals are also less likely to be passed on to the next generation, this is called negative selection. expression.
The researchers say that they have found evidence of negative selection – in this case, the removal of harmful gene variants – in some traits. And the most convincing evidence is those related to cardiovascular function and reproductive function.
For cardiovascular function, the team found changes related to waist circumference and waist-to-hip ratio. An excess amount of fat around the waist has been previously found to be significantly associated with cardiovascular disease risk. The team also found evidence of changes in blood pressure.
But a woman’s age at menopause – in relation to fertility – shows the most dramatic change. The age at which women first menstruated and gave birth for the first time are significant markers, as they show a strong correlation between fertility and matching genes.
Evolution involves positive and negative selection. (Photo: Suckhoedoisong).
This is not the first time scientists have analyzed data from the Biobank about evolutionary changes in humans. Last year, researchers at the University of California, Irvine studied the DNA of more than 500,000 individuals to examine both positive and negative selection processes. They found that evolution would benefit men with high BMIs (perhaps due to large muscle mass) and in women who give birth early.
In a 2011 study, scientists reported that evolutionary changes develop fairly steadily but are not easily noticeable. Because it takes about a million years for an evolutionary trait to develop and survive. This new study may not help us realize the massive changes that evolution has had on humans, but it does help science understand more about nature’s evolution and how selection works.
“Negative selection prevents ‘bad’ mutations from spreading throughout the population. This means that common DNA variants may have little or no effect on traits. will help us better understand the genetic basis of complex traits and help create future experiments in the study of complex traits and medical genomics,” Zeng said.
The team’s research was published in the journal Nature Genetics.