Wednesday 12 March 2014

Europeans have ‘got whiter’ due to natural selection in past 5,000 years, scientists say


Europeans have ‘got whiter’ due to natural selection in past 5,000 years, scientists say



Experts have found a few changes in European DNA due to natural selection. These changes have made skin’s European humans to become much ‘whiter’ through the last 5,000 years. Recently, there has been a research based on the comparison of ancient and current DNA. The study has shown a genetic distinction between our ancestors and us. This difference, due to its relation with hair, eye pigmentation and skin, has caused the descendants to be ‘whiter’.

The results were not the ones scientists expected as in theory darker phenotype has always had preference over whiter phenotype. The surprising result has lead to several explanations.
Mark Thomas UCL’S professor has said that this change over the past thousand years could have been a natural adaptation to reduction in the amount of sunlight received in northern latitudes.
Sandra Wilde, the lead report author from Mainz’s Johannes Gutenberg University, gives us another possible explanation. This explanation could be related to group affiliation, as the change on the hair and eye colour might have an important role in the selection of a partner.

However, there is a last explanation that says that this result could be connected to a specific timeframe. While archeologists are trying to find the exact point when this distinction in our genome happened, researches discuss about what could have provoked this change. The final conclusion that they reached is that all this may be caused by positive selection.

I have chosen this article because the title appealed to me so much. I still continuo without understanding why natural selection had chose whiter phenotype, as being whiter makes us more vulnerable to ray of sunlight. Experts have concluded that this lighter skin is due to the reduced level of sunlight in northern areas. However, climate change is producing an increase of temperatures and also an increase in the amount of sunlight received, so I think that there would be another timeframe where the darker phenotype would take preference again.

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