Updated 8:44 AM EDT, Wed, Aug 18, 2021

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Study: Natural Selection Still Key to Human Evolution Despite Low Birth Rates


(Photo : Pixabay) A new study reveals that humans are still evolving based on natural selection.

A new study takes into consideration how cultural influences greatly affect the process of natural selection, which remains the driving force of human evolution even if overall birth and death rates are at an all time low compared to any point in human history.

A team of researchers from the Uppsala University in Sweden took into account birth records, marriages and even death records from 10,000 individuals from several churches in Finland beginning from the 18th century, said lead researcher Elisabeth Bolund.

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During the 18th and 19th centuries, the team discovered that four to 18 percent of factors such as lifespan, number of members in the family they belong to and age gaps of the first and last childbirth were largely determined by genetic factors. The rest of the factors were influenced by environmental ones.

Bolund said this finding is exciting news since it shows that if genes can be affected by these traits, it also means people have the ability to change their response to natural selection. An investigation of the genetic basis of these complex traits shows their ability to change via evolution.

The findings also show that the genetic influence when it comes to the timing of reproduction and size of a family are higher in modern times compared to the last few centuries. This suggests that genetic differences still continue to affect modern evolution.

Bolund also said that modern societies have more freedom for individuals to express their genetic predispositions, especially since social influences are more relaxed and leads to more genetic differences and reproductive patterns.

The team also found out that the genetic basis of reproductive traits and longevity did not alter over time. This is good news since this can determine current patterns of natural selection in order to predict the trend of modern human populations over the next few generations.

This is also pivotal in predicting population responses when it comes to epidemics, ageing populations and infertility. This study was published in the journal, Evolution. 

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