The price of silent mutations
Everyone has on average 400 flaws in their DNA, a UK study suggests…Most are “silent” mutations and do not affect health, although they can cause problems when passed to future generations…Others are linked to conditions such as cancer or heart disease, which appear in later life, say geneticists.
The evidence comes from the 1,000 Genomes project, which is mapping normal human genetic differences, from tiny changes in DNA to major mutations.
In the study, 1,000 seemingly healthy people from Europe, the Americas and East Asia had their entire genetic sequences decoded, to look at what makes people different from each other, and to help in the search for genetic links to diseases.
The new research, published in The American Journal of Human Genetics, compared the genomes of 179 participants, who were healthy at the time their DNA was sampled, with a database of human mutations developed at Cardiff University.
It revealed that a normal healthy person has on average about 400 potentially damaging DNA variations, and two DNA changes known to be associated with disease.
“Ordinary people carry disease-causing mutations without them having any obvious effect,” said Dr Chris Tyler-Smith, a lead researcher on the study from the Wellcome Trust Sanger Institute, Cambridge.
He added: “In a population there will be variants that have consequences for their own health.”
The research gives an insight into the “flaws that make us all different, sometimes with different expertise and different abilities, but also different predispositions in diseases,” said Prof David Cooper of Cardiff University, the other lead researcher of the study.
“Not all human genomes have perfect sequences,” he added. “The human genome is packed with pervasive, architectural flaws.”
It has been known for decades that all people carry some genetic mutations that appear to cause little or no harm. Many are only damaging if they are passed on to children who inherit another copy of the faulty gene from the other parent.
In others – around one in ten of those studied – the mutation causes only a mild condition, appears to be inactive, or does not manifest itself until later life.
Databases of human mutations, like the one at Cardiff University, will have increasing importance in the future, as we move into the era of personalised medicine…But as DNA sequencing becomes more widespread, ethical dilemmas will arise about what to tell people about their genes, especially when many risks are uncertain.
We all understand the range of dead ends available for time-wasting by ethicists. Especially those with one or another superstition to justify. I come down – in advance – on the side of the simplest and most democratic premise: knowledge is always useful. I don’t care if someone decides if it’s scary or silly – I have the right to know.
Scientists have used genome sequencing technology to control an outbreak of the superbug MRSA in a study that could point to faster and more efficient treatment of a range of diseases…
MRSA, or Methicillin-Resistant Staphylococcus Aureus, is a drug-resistant bacterial infection, or superbug, and major public health problem. When outbreaks occur in hospitals it can lead to the closure of whole wards and lengthy investigations.
The bug kills an estimated 19,000 people in the United States alone each year, and even when the infection is successfully treated it can double the average length of a hospital stay and thereby increase healthcare costs.
A team of scientists…used samples from a 2009 MRSA outbreak in a hospital neo-natal intensive care ward to recreate and respond to it, as if in real time. They found that genome sequencing produced results in roughly 24 hours, using the latest technology from Illumina, gave much more detailed information.
The researchers were able to identify the particular strain of MRSA causing the outbreak, and which strains were not, quickly enough to feed back into treatment and nip the outbreak in the bud faster than current clinical testing methods.
“I think we are at the very beginning of an explosion of evidence to support the use of whole genome sequencing in public health,” Sharon Peacock of Cambridge University, who led the study, told Reuters.
The research…comes hot on the heels of similar work done on MRSA and Clostridium difficile by a team from Oxford University with Illumina and a group of hospitals in Britain…Oxford microbiologist Derrick Crook, who worked on that project, said that as recently as two years ago “it would have taken months and thousands of pounds to process such informative sequence information on hospital infections…”
The researchers say this kind of fast genome sequencing could eventually form the basis for a regional or national infection surveillance program designed to head off MRSA outbreaks before they happen. It could also be used for outbreaks of food-borne infections like salmonella or E.coli…
Peacock says the next stage is to develop software that interprets the data in a way doctors can both understand and use in a hospital…She also points out that while the study indicates this kind of sequencing is cheaper than existing, less detailed, tests, there will also need to be rigorous cost-benefit analysis.
Still – the results demonstrate how technology, advanced methods, combinations of the latest proven means can eliminate days and dollars from the process of investigation and treatment of previously daunting illness.
MRSA is one of the worst. A family of death and destruction worthy of being weaponized in the minds of our planet’ worst politicians. It is a deadly foe and we appear to have moved forward to a better place in the arsenal of healthcare – courtesy of progressive technology.