The Human Genome Project at 15: what have we learned?
Wednesday, April 25, 2018. Author Dr. Haran Sivapalan
Wednesday, April 25, 2018. Author Dr. Haran Sivapalan
65 years ago today, scientists James Watson and Francis Crick (with the essential help of Maurice Wilkins and Rosalind Franklin) published a paper in Nature entitled The Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid.
The paper described how the instructions for human life were contained within the characteristic double-helix of the DNA molecule. Imagine a ladder twisted around its vertical axis: that's the DNA double helix. The rungs of this ladder are pairs of nitrogen bases, with each base given the letters A, T, C or G. The exact sequence of these letters determines what proteins our bodies make. In turn, these proteins influence everything from what color our hair is to whether we have a sweet tooth.
Fast forward 50 years and scientists have now successfully determined the exact order of all 3 billion base pairs in our DNA sequence. The 14th April 2003 marked the end of a gargantuan, 13-year international effort to map our entire genetic code: The Human Genome Project.
Needless to say, without this extraordinary scientific accomplishment, FitnessGenes would not exist. In celebration of National DNA Day, let's take a look at some of the things the Human Genome Project has helped us achieve.
When it comes to exercise, nutrition and fitness, people have long suspected that genetics have a significant role to play. We've all been in awe of that athlete who has bags of ‘innate ability', or envious of that person who's always eating but seems to ‘naturally' maintain a trim figure.
Studies of twins and families demonstrate that individuals who are more closely genetically related are more likely to be similar on traits such as endurance ability, muscle strength, and body composition, even when brought up in vastly different environments. Although such twin and family aggregation studies implicate genetics in health and fitness more broadly, they do not point to specific genes – stretches of DNA that code for proteins.
Thanks to the Human Genome Project, however, we have now not only been able to pinpoint individual genes in our genome, but we've also elucidated the function of many of these genes. Of the roughly 20,000 genes that span across our entire DNA sequence (or ‘genome'), several are now known to influence our diet, fitness, and physiology.
Here at FitnessGenes, we analyze 45 of such genes, with this number soon to expand as more robust research becomes available. On this note, geneticists and sports scientists are further scrutinizing our genome for more relevant genes and slowly filling in a Human Gene Map for Performance and Health-related Fitness Phenotypes (see Fig 1).
Another thing we learned from the Human Genome Project is that genetically speaking, we are very similar to one another. Any two people share about 99.5-99.9% of their DNA sequence. Yet, while only a miniscule 0.1% - 0.4% of our genome varies between individuals, we are all significantly different. We look different to each other, we behave differently, and we respond differently to diet and exercise.
Just as DNA explains human similarity, analysis of the genome also helps to explain human variation. Scattered across the genome are single letter changes in the DNA code, called Single Nucleotide Polymorphisms (SNPs – pronounced ‘snips'). These SNPs, depending where exactly in our DNA sequence they occur, can have profound impacts on our response to training and nutrition.
For example, if your DNA sequence has a letter T at a specific site within your ACTN3 gene, your body will not produce the protein alpha-actinin 3 – a component of fast twitch muscle fibers. If, however, there is a letter C instead of T at the same site, your muscles will produce the alpha-actinin 3 protein, and you may respond better to resistance training.
With developments in DNA analysis (genotyping) technology, it's also now easier to investigate which specific SNPs and gene variants are linked to various health and fitness outcomes. One of the legacies of the Human Genome Project is the growth of the Genome-Wide Association Study (GWAS), a research tool which allows scientists to rapidly scan our entire genome for genetic markers associated with various traits. In 2011, for example, scientists successfully used GWAS to identify 21 SNPs that influence changes in VO2max following exercise training programs.
If, due to variations in our genes, we each respond differently to diet and exercise, is it possible to tailor nutrition and workout plans that account for these genetic variations? The answer is yes! It's all part the nascent personal genomics revolution.
By sequencing our entire DNA sequence, the Human Genome Project essentially uncovered the recipe book for humankind. Now, more and more people are finding out about their own personal recipe book. Armed with this knowledge, people are learning about their own internal physiology and, in doing so, are empowered to make the dietary and training decisions best suited to them. Previously, a lot of these decisions would have been based on guesswork.
Based on your DNA, we can now tell you: how well you metabolize fat versus carbohydrate, how long you should recover between sets, whether you're likely to be a morning lark or night owl or even when is best to drink a cup of coffee.
So, from everyone at FitnessGenes, we wish you a Happy National DNA Day!
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