An ancient coronavirus epidemic 25,000 years ago could help us treat current Covid-19 sufferers, a study has found.
Scientists have identified a set of 42 genes which were altered after coming into contact with coronavirus some 900 generations ago.
The adaptations were caused by a "multigenerational coronavirus epidemic" among East Asian populations, the researchers from the USA and Australia concluded.
This likely triggered an "arms race", similar to today's worldwide rush to find a vaccine against Covid-19, the study suggests.
The scientists studied 26 populations from five regions in East Asia using data from the 1000 Genomes Project - the largest public catalogue of human genomic data.
These findings could help scientists currently working on developing treatments for Covid-19, as drugs could be tailored to target the 42 genes identified as being impacted by the virus in the past, the researchers say.
They also believe future pandemics could be prevented altogether.
"Modern human genomes contain evolutionary information tracing back tens of thousands of years, which may help identify the viruses that have impacted our ancestors – pointing to which viruses have future pandemic potential," the study states.
"By revealing the identity of our ancient pathogenic foes, evolutionary genomic methods may ultimately improve our ability to predict – and thus prevent – the epidemics of the future."
The study, which is yet to be peer reviewed, comes as scientists continue to work on ways of identifying what makes some people particularly badly affected by Covid-19, and how they can be treated.
They believe there could be genetic differences between individuals which cause some to experience more severe symptoms than others.
These differences in DNA are now being tracked by researchers who believe they offer a route to developing new drugs that could halt many of the worst consequences of suffering from Covid-19.
“The crucial point is that by understanding the impact of gene variants in the body we can now think about finding drugs that could block their pathways and help patients,” said Jeffrey Barrett, of the Wellcome Sanger Institute’s Covid-19 genomic surveillance programme.
“The bad news is that it can take years of experiments to find treatments this way. The good news is that there are now so many scientists working on this kind of thing that we might still get some quick answers.”
Previous research by King's College London suggested that genes are around 50 per cent responsible for how badly infected people suffer from certain symptoms.
In particular, it showed a strong genetic link to delirium, fever, fatigue, shortness of breath, diarrhoea and the loss of taste and smell.