Geneticists from Trinity have used evolutionary history to isolate a short list of genes that may cause a huge number of diseases.
Their findings allow us to better understand human disease and were published in the international scientific journal Nature Communications on February 8th.
The researchers found that relatively few genes, dubbed “goldilocks genes”, are candidates for a diverse range of neurodevelopmental conditions including autism spectrum disorders, schizophrenia, Attention Deficit Hyperactivity Disorder (ADHD), intellectual disability, developmental delay, and epilepsy.
The human genome contains over 20,000 genes, which have the codes used to produce specific proteins in the body. The Trinity geneticists focused on regions, within the human genome, that are duplicated or deleted in some individuals. These regions, termed “copy number variants”, are very common in humans.
The presence of these regions does not always result in noticeable differences between individuals. However, variations in these regions are associated with a variety of debilitating disorders and diseases. These disease-causing regions, within the human genome, contain a vast number of genes and it has been very difficult to identify the specific genes that cause diseases.
Prof Aoife McLysaght of Trinity’s Department of Genetics – who recently volunteered facilities in her lab to US-based researchers stuck outside the US following Donald Trump’s immigration ban – spoke about the discovery in a press release.
McLysaght explained that their “idea was that there must be some genes within these regions with ‘Goldilocks’ properties: too much or too little duplication, and things don’t work properly. The number of copies must be just right”.
The Trinity team looked at humans evolutionary history to discover which genes don’t tolerate changes amounts of duplication or deletion over evolutionary time. The key is in the presence of these genes within disease-causing regions of the human genome, according to the team of Trinity geneticists. This is particularly important for genes that are key to human development at early embryonic stages.
The team also found that, across different mammal species – rabbits, gorillas, dogs etc – regions linked to developmental disorders had far less variation in the number of gene copies than for regions where variations are not associated with disorders.
This means that wider variations in the number of gene copies may continue to change in these non-disorder associated regions, but no in disease-linked regions. The effects of this would be too physiologically serious, meaning that an individual would not be able to pass them onto their children.
McLysaght also said that their “work demonstrates that our evolutionary history is useful for understanding human disease. These metrics also allow us to home in on a short list of genes as candidates for the diseases in question — some of which are seriously debilitating”.
She believes that “isolating specific genes that are linked to these disorders will increase our understanding of how and why they develop”. This research could greatly benefit people dealing with these disorders and McLysaght said that their research could “lead to better diagnostics, and potentially help to develop therapies further down the line”.