While we all share the same genetic code, how those genes express themselves at an individual level presents a challenge for scientists in developing medicines and dietary advice.
Now scientists at the Institute of Food Research (IFR) have completed what they say is one of the first studies to define how unique we are onthe genetic level. The initial study on 18 individuals found that the way our genes function varies significantly, particularly in some key areas including the immune system.
Of the 14,000 genes analysed, 3,302 were identified as varying significantly in their expression among human volunteers. Some of the variation was what might have been expected due to age, genderand body mass index. However the team found considerable variation in the expression of genes covering a wide range of biological functions, such as those regulating antibody production.
While the main findings are important for determining how individuals may respond to different medicines, it could also be used for determining nutritional needs. The fact that day-to-day variationwithin individuals was so low suggests that detecting even small changes through adjustments to diet or nutrition should be feasible, the team stated.
"We are the same, but different, and the validity of nutrition research is dependent on knowing just how different we are," said John Eady, a research scientist on the team. "Withthis research, the impact of diet can be more accurately measured and early signs of disease can be more easily predicted."
Research leader Ruan Elliott said his team studied "gene expression", the process by which genes are activated to make proteins that in turn carry out a range of functions in the body.
Differences in gene expression can translate into visible characteristics, such as eye and hair colour, and can also affect how we respond to different medicines and foods.
The team studied gene expression in white blood cells, which are involved in disease response. Such cells can alert scientists to minor changes that occur before disease sets in. The study definedthe normal level of variability of gene expression in healthy people so minor changes can be detected.
The study allowed for maximum variation by taking a total of five samples from each of 18 individuals every eight days.
"As with the human genome project, our research involved relatively few people, but it tells an important story that will help scientists all over the world accurately make sense of geneticinformation", Elliott stated. "We have made the data freely available."
The research was funded by the Biotechnology and Biological Sciences Research Council and is part of ongoing work to investigate diet and gene interactions. It will be published in PhysiologicalGenomics.