Scientists believe that natural selection may phase out genetic mutations that are largely attributed to conditions such as Alzheimer’s disease.
Other memory-related conditions and even asthma may disappear completely as a result of natural selection. Although the transition may take thousands of years, the chances of this happening look very high.
Despite drastic changes in the world resulting from events such as natural disasters and war, life continues to prevail and adapt to its surroundings – this is a large part of natural selection.
Researchers believe that humans have a long way to go on the path of evolution. Recent studies have shown that genetic variants affecting fertility may have a permanent effect on certain severe health conditions.
One finding showed that on average, people born with one of the ApoE4 genes die quicker than those without it. The theory is that if people with this gene die at a young age, then future generations will be less likely to inherit the gene, paving the way for an eventual extinction of the gene.
“If men with ApoE4 have 0.1% fewer children on average than men without them, this would be enough for these variants to be removed quickly by natural selection,” Hakhamanesh Mostafavi said. Mostafavi is the lead researcher in this particular study.
Another finding showed that the CHRNA3 gene, which is related to higher susceptibilities to lung cancer, may also be phased out with time. The theory is that people with the gene are failing to live as long as those without, and therefore the gene is slowly dropping off.
The findings were a result of a study that took place in the UK and the US and over 210,000 people were tested in aide of the research. Despite no guarantee that these genes will disappear over time, the possibilities are high.
“A trait associated with a longer lifespan in one population today may no longer be helpful several generations from now or even in other modern day populations,” Mostafavi said.