50,000 years ago in the Middle Palaeolithic, Covid-19 is a far-off futuristic blip. However, scientists today are suggesting that a mortality risk factor due to the virus can be traced back to this time, when our ancestors’ interbred with Neanderthals.
A study of our genetic coding has uncovered multiple genes related to our immune system and pathogen resopnse, that have been inherited from Homo neanderthalensis.
These genes would have benefitted newly arriving Homo sapiens populations in Europe, who would have been ill equipped for the different climate and new pathogens. These disease resistance genes have thus remained intact in modern humans through positive selection (when a trait granted by a gene is favourable, and thus passed down through surviving members of a species)
However current research suggests these previously beneficial genes may increase the chances of being put on a ventilator due to Covid by 30%.
A recent study compared the DNA of severely ill Covid-19 patients with controls. They uncovered a short DNA segment uniquely found in those suffering from severe respiratory problems as a result of Covid.
This small segment of DNA plays a significant role in our immune response. Found on chromosome 3, it was already identified as a risk locus for respiratory failures – a very dangerous collection of genes if a deadly pandemic sweeps across the world.
This same stretch of DNA was also found in well-studied Neanderthal genomes – leading us to believe that it is a relic of the once valuable disease resistance genes inherited from our Neanderthal ancestors.
More worryingly, this gene variant is strongly associated with certain populations. So, alongside your health, socioeconomic status, age, or sex, a new risk factor may also be at play – your genetics.
Through the Human Genome Project, scientists established the population trends of this genetic trait. They found that up to 50% of South Asians carry the gene, but only 16% of Europeans do.
A surprising discovery is that as much as 13% of the population of Bangladesh is homozygous for this trait. This means individuals carry two copies of the gene, hugely inflating their risk at developing severe symptoms of Covid-19 if the gene is indeed directly linked.
This statistic was even used to tentatively explain why populations with Bangladeshi origin in the UK experienced such high mortalities from the pandemic.
Although it would be incredibly satisfying to lay the blame of SARS-CoV-2 on a singular cause, we must be careful not to wholeheartedly accept claims that a small section of DNA inherited by Neanderthals makes you more vulnerable – especially when the percentage of Neanderthal DNA within modern humans differs in certain populations.
Attributing diseases and illnesses to the ethnic origins of populations is a risky game. All too quickly, biological superiority is assumed and a few key words spring to mind: racism and eugenics. The disproportionate nuber of deaths amongst the BAME communities that has been observed both in the UK and the US is likely not a result of genetic differences, but of social inequalities.
These are often reflected in other health conditions such as obesity, heart disease and diabetes – which have all been linked to, low socioeconomic status and a poor access to healthcare.
Before we begin to examine our genetic composition and focus on minute differences between populations, we should first achieve as level a playing field as possible for all individuals, regardless of heritage or status within a society. We can’t change our genetics, but perhaps by understanding them a little better we can begin to make small steps towards a better world.
Image: Paul Hudson via Flickr