By Maeve McCann, TCD

What do you associate with the word mutation? Is your own unique traits as a human? Or is it the most recent Covid variant? Trends in Google search data from Ireland show that recent peaks of searches for "mutation" coincide with key dates in the development of the pandemic; namely March 2020, Christmas 2020 and late 2021. These were times of anxiety and societal upheaval as we adjusted to a new and changing virus. Within this context it might be hard for us to see past the negative emotions we might associate with the word mutation.

Like all life, we are the result of billions of years of mutations and evolution. Mutations are like the weather in that they can be good, bad or neutral and are mostly dependent on the context they occur in. They are any kind of change in the sequence of DNA which is composed of 4 chemicals known by the letters A, T, C and G. The complete DNA in any organism or the genome, is converted by the body into proteins, which become our living tissues and regulate our body and DNA. The complexity of life arising from this basic mechanism is astounding, however none of it would be possible without mutations.

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

From RTÉ Lyric FM's Culture File, interview with Prof Paige Harden about her book The Genetic Lottery and how genetics might be used against discrimination and inequality

The types of mutations which have punctuated the evolutionary journey to humans include everything from small mutations, to massive restructuring of the genome. Mutations are predominantly neutral in effect with no obvious repercussions for survival, but can be used for identifying species or individuals through their resulting unique genetic fingerprint. However some will lead to either a greater chance of survival or a reduced chance of survival. This is true whether we're talking about a virus, sea sponge or a human.

One type of massive mutation, which can give a greater chance of survival especially in extreme environments, is to have a duplication of the genome. In plants, a genome duplication can lead to beneficial effects such as bearing bigger fruit. Cultivated strawberries have experienced so many genome duplications that they can have up to 10 copies of their genome!

Many organisms alive today experienced ancient genome duplications, contributing to the great diversity of life on earth by giving evolution more copies of DNA to work with. We know that vertebrates experienced ancient genome duplications not shared by other animals, one in common with lampreys and another just within jawed vertebrates. These were important mutations which increased the number of genes controlling things such as body plan. If you were wondering what makes you more complex than a fruit fly, one answer is genome duplications!

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

From RTÉ Radio 1's Drivetime, personal trainer Karl Henry on how six packs are 72% down to genetics

But what are the mutations which make us human? We differ from our closest living relative, chimps, by between 3 to 4%. Many of these differences are neutral, but some have been selected for during evolution and contribute to our unique biology. This includes changes in our genome affecting muscle function, digestion, immunity and neurodevelopment.

All humans share approximately 99.9% DNA today, with only a small portion of the genome giving rise to the uniqueness of each person on earth. Common differences across the human population are small mutations where there is a base change, such as from an A to a T. These mutations are used to model our individual ancestries and the population histories of different peoples.

Studying these mutations has allowed us to reconstruct the human evolutionary journey from the earliest humans in Africa through to the first settlers in Ireland a few millennia ago. Using a combination of genomes from ancient and modern humans, researchers in Trinity College found that the Irish genome was established in the Bronze Age, over 4,000 years ago, and has remained similar through to today.

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

From RTÉ Radio 1's Today with Claire Byrne, Dr Jeffrey Barrett from the Sanger Institute in Finland on genomic sequencing

Key genetic mutations found frequently in people with Irish ancestry contribute to our pale skin, ability to digest milk and increase our risk of inheriting cystic fibrosis and hemochromatosis. We can also use mutations to model regional differences in modern-day people from Britain and Ireland, revealing geographical barriers to our ancestors' movement and historical migration events in Ireland, including the Norman conquest, Viking period and British plantations.

This is just a snapshot of the many ways that mutations have affected our lives and can be used to examine our lives. Millions of years of evolution via genetic mutation has led to our existence as humans, on a planet full of biological diversity. Mutations may have defined our recent lives in the form of a coronavirus evolving in real-time, but our ability to study the changes in DNA has not only helped us to manage the pandemic in an unprecedented way, it has also allowed us to study how we became human. Mutations are what make us human and what make you, you.

Maeve McCann is a PhD student in human population genomics at TCD.


The views expressed here are those of the author and do not represent or reflect the views of RTÉ