Genomic studies, which have generated important discoveries regarding human health and behaviour, are severely limited by the lack of racial diversity, say Oxford researchers who found that people studied continue to be overwhelmingly of European descent. The research from the University of Oxford in the UK is the first to show that subjects of genetic discoveries are concentrated in a handful of countries - the UK, US and Iceland, and have specific demographic characteristics.
Researchers caution that this lack of diversity has potentially huge implications for the understanding and applications of genetic discoveries.
The study, published in Communications Biology, contributes to a richer understanding of a multitude of facets which shape genomic bias over time.
Researchers reviewed nearly 4,000 scientific studies between 2005 and 2018. These studies have identified multiple genetic groups related to diseases such as type 2 diabetes, Alzheimer's, to psychiatric disorders, physical, behavioural and psychological traits.
The study examined the explosion in the number of people studied, number and strength of genetic association discoveries, and growth and variation in the number of outcomes (or 'phenotypes') studied.
It also looked at who was being studied in terms of ancestral background, geographical location and demographics, but also who was conducting the research, including the networks and characteristics of the researchers themselves. Despite a staggering growth in sample sizes, the number of traits and diseases studied and genetic discoveries, findings from the study reveal that ancestral diversity has stalled and that non-white groups are still massively under-represented.
By extending research in this area they show that this has varied considerably over time and that when non-European ancestry groups are included, it is often only to 'replicate' results, as opposed to fundamental new genetic discoveries.
Moving beyond ancestral diversity, the researchers estimate for the first time that 72 per cent of the repeatedly utilised data came from individuals recruited from just three countries; the UK (40 per cent), US (19 per cent) and Iceland (12 per cent).
Data was subject not only to geographical concentration, but also featured a higher than anticipated proportion of older people, women and in some of the most prominently used data, also subjects with higher socioeconomic status and better health.
"Genetic discoveries offer exciting medical possibilities, but without increasing the diversity of people studied and environments they live in, the usage and returns of this research are limited," said Melinda Mills, lead author of the study.
"There is increasing recognition that our health outcomes are a complex interplay between genes and the environment -- or in other words nature and nurture -- yet most discoveries have been taken from populations that are very similar, with limited environmental variation," Mills said.