In a world filled with natural disasters, war, and growing risk of incurable infections, one study is shining a little ray of hope that perhaps the future won’t be as grim as we imagine. The study found subtle evidence to suggest that certain genetic diseases, such as Alzheimer’s and asthma, may be weeded out by natural selection. Sure, it may take a few thousand years, but at least our future generations would have something to look forward to.
Natural selection is nature’s way to ensure life keeps on living despite drastic changes in environment and lifestyle. You may think that humans have reached their evolutionary peak, but the research found evidence that genetic variants that influence fertility in the U.S. and UK are slowly changing, and may be working to weed out certain mutations that lead to a number of serious health conditions, The Independent reported.
The data showed that people with a certain variation in the ApoE4 gene seem to die much earlier than those without the variation. This finding is noteworthy because this variation is linked to Alzheimer’s disease. If people with this gene die too young to reproduce, they will not be able to pass the gene on to future generations, which would cause the gene and all the traits associated with it to die out as well.
“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,” explained study lead researcher Hakhamenesh Mostafavi, The Telegraph reported.
In addition, the research noted a drop in the frequency of a certain mutation of the CHRNA3 gene, starting in middle age. This suggests individuals with this genetic variation do not live very long, perhaps not even long enough to reproduce. This matters because the CHRNA3 gene is associated with increased risk of smoking and susceptibility to lung cancer.
These results are based on DNA testing of 210,000 people from the UK Biobank and Kaiser Permanente in California. It is now published online in PLOS Biology. The team noted that their results can't be taken as proof that these genes will die out. Although the researchers were able to note varying differences in these genetic mutations, and can speculate what these variations may mean over time, there is no way to accurately predict how human evolution will continue.
"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," explained Mostafavi.
In addition, even if evolution did weed out these genes, it likely would take several thousand years for effects to be seen. While erasing Alzheimer's disease from our genome would be ideal, in the meantime, researchers are working on different ways to treat and ultimately cure this condition.
Source: Mostafavi H, Berisa T, Day FR, et al. Identifying genetic variants that affect viability in large cohorts. PLOS Biology . 2017