THE
HUMAN DNA IS A BIOLOGICAL INTERNET and superior in many aspects to the
artificial one. Russian scientific research directly or indirectly
explains phenomena such as clairvoyance, intuition, spontaneous and
remote acts of healing, self-healing, affirmation techniques, unusual
light/auras around people (namely spiritual masters), mind’s
influence on weather patterns and much more. In addition, there is
evidence for a whole new type of medicine in which DNA can be influenced
and reprogrammed by words and frequencies withoutcutting out and replacing single genes.
The Great DNA Data Deficit: Are Genes for Disease a Mirage?
Jonathan Latham and Allison Wilson
Just before his appointment as head of
the US National Institutes of Health (NIH), Francis Collins, the most
prominent medical geneticist of our time, had his own genome scanned for
disease susceptibility genes. He had decided, so he said, that the
technology of personalised genomics was finally mature enough to yield
meaningful results. Indeed, the outcome of his scan inspired The Language of Life, his recent book which urges every individual to do the same and secure their place on the personalised genomics bandwagon.
So, what knowledge did Collins’s scan
produce? His results can be summarised very briefly. For North American
males the probability of developing type 2 diabetes is 23%. Collins’s
own risk was estimated at 29% and he highlighted this as the outstanding
finding. For all other common diseases, however, including stroke,
cancer, heart disease, and dementia, Collins’s likelihood of contracting
them was average.
Predicting disease probability to within a
percentage point might seem like a major scientific achievement. From
the perspective of a professional geneticist, however, there is an
obvious problem with these results. The hoped-for outcome is to detect
genes that cause personal risk to deviate from the average.
Otherwise, a genetic scan or even a whole genome sequence is showing
nothing that wasn’t already known. The real story, therefore, of
Collins’s personal genome scan is not its success, but rather its
failure to reveal meaningful information about his long-term medical
prospects. Moreover, Collins’s genome is unlikely to be an aberration.
Contrary to expectations, the latest genetic research indicates that
almost everyone’s genome will be similarly unrevealing.
We must assume that, as a geneticist as
well as head of NIH, Francis Collins is more aware of this than anyone,
but if so, he wrote The Language of Life not out of raw
enthusiasm but because the genetics revolution (and not just
personalised genomics) is in big trouble. He knows it is going to need
all the boosters it can get.
What has changed scientifically in the
last three years is the accumulating inability of a new whole-genome
scanning technique (called Genome-Wide Association studies; GWAs) to
find important genes for disease in human populations1. In
study after study, applying GWAs to every common (non-infectious)
physical disease and mental disorder, the results have been remarkably
consistent: only genes with very minor effects have been uncovered
(summarised in Manolio et al 2009; Dermitzakis and Clark 2009). In other
words, the genetic variation confidently expected by medical
geneticists to explain common diseases, cannot be found.
There are, nevertheless, certain
exceptions to this blanket statement. One group are the single gene,
mostly rare, genetic disorders whose discovery predated GWA studies2.
These include cystic fibrosis, sickle cell anaemia and Huntington’s
disease. A second class of exceptions are a handful of genetic
contributors to common diseases and whose discovery also predated GWAs.
They are few enough to list individually: a fairly common single gene
variant for Alzheimer’s disease, and the two breast cancer genes BRCA 1
and 2 (Miki et al. 1994; Reiman et al. 1996). Lastly, GWA studies
themselves have identified five genes each with a significant role in
the common degenerative eye disease called age-related macular
degeneration (AMD). With these exceptions duly noted, however, we can
reiterate that according to the best available data, genetic
predispositions (i.e. causes) have a negligible role in heart disease,
cancer3, stroke, autoimmune diseases, obesity, autism,
Parkinson’s disease, depression, schizophrenia and many other common
mental and physical illnesses that are the major killers in Western
countries4.
For anyone who has read about ‘genes for’
nearly every disease and the deluge of medical advances predicted to
follow these discoveries, the negative results of the GWA studies will
likely come as a surprise. They may even appear to contradict everything
we know about the role of genes in disease. This disbelief is in fact
the prevailing view of medical geneticists. They do not dispute the GWA
results themselves but are now assuming that genes predisposing to
common diseases must somehow have been missed by the GWA methodology.
There is a big problem, however, in that geneticists have been unable to
agree on where this ‘dark matter of DNA’ might be hiding.
If, instead of invoking missing genes, we
take the GWA studies at face value, then apart from the exceptions
noted above, genetic predispositions as significant factors in the
prevalence of common diseases are refuted. If true, this would be a
discovery of truly enormous significance. Medical progress will have to
do without genetics providing “a complete transformation in therapeutic
medicine” (Francis Collins, White House Press Release, June 26, 2000).
Secondly, as Francis Collins found, genetic testing will never predict
an individual’s personal risk of common diseases. And of course, if the
enormous death toll from common Western diseases cannot be attributed to
genetic predispositions it must predominantly originate in our wider
environment. In other words, diet, lifestyle and chemical exposures, to
name a few of the possibilities.
The question, therefore, of whether
medical geneticists are acting reasonably in proposing some hitherto
unexpected genetic hiding place, or are simply grasping at straws, is a
hugely significant one. And there is more than one problem with the
medical geneticists’ position. Firstly, as lack of agreement implies,
they have been unable to hypothesise a genetic hiding place that is both
plausible and large enough to conceal the necessary human genetic
variation for disease. Furthermore, for most common diseases there
exists plentiful evidence that environment, and not genes, can
satisfactorily explain their existence. Finally, the oddity of denying
the significance of results they have spent many billions of dollars
generating can be explained by realising that a shortage of genes for
disease means an impending oversupply of medical geneticists.
You will not, however, gather this from
the popular or even scientific media, or even the science journals
themselves. No-one so far has been prepared to point out the weaknesses
in the medical geneticist’s position. The closest up to now is from
science journalist Nicholas Wade in the New York Times who has suggested that genetic researchers have “gone back to square one.”
Even this is a massive understatement, however. Human genetic research
is not merely at an impasse, it would seem to have excluded inherited
DNA, its central subject, as a major explanation of most diseases.
The failure to find major ‘disease genes’
Advances in medical genetics have
historically centered on the search for genetic variants conferring
susceptibility to rare diseases. Such genes are most easily detected
when their effects are very strong (in genetics this is called highly
penetrant), or a gene variant is present in unusually inbred human
populations such as Icelanders or Ashkenazi Jews. This strategy, based
on traditional genetics, has uncovered genes for cystic fibrosis,
Huntington’s disease, the breast cancer susceptibility genes BRCA 1 and
2, and many others. Important though these discoveries have been, these
defective genetic variants are relatively rare, meaning they do not
account for disease in most people2. To find the genes
expected to perform analogous roles in more common diseases, different
genetic tools were needed, ones that were more statistical in nature.
The technique of genome wide association
(GWA) was not merely the latest hot thing in genetics. It was in many
ways the logical extension of the human genome sequencing project. The
original project sequenced just one genome but, genetically speaking, we
are all different. These differences are, for many geneticists, the
real interest of human DNA. Many thousands of minor genetic differences
between individuals have now been catalogued and medical geneticists
wanted to use this seemingly random variation to tag disease genes.
Using these minor DNA differences to screen large human populations, GWA
studies were going to identify the precise location of the gene
variants associated with susceptibility to common disorders and
diseases.
To date, more than 700 separate GWA
studies have been completed, covering about 80 different diseases. Every
common disease, including dozens of cancers, heart disease, stroke,
diabetes, mental illnesses, autism, and others, has had one or more GWA
study associated with it (Hindorff et al. 2009). At a combined cost of
billions of dollars, it was expected at last to reveal the genes behind
human illness. And, once identified, these gene variants would become
the launchpad for the personalised genomic revolution.
But it didn’t work out that way. Only for
one disease, AMD, have geneticists found any of the major-effect genes
they expected and, of the remaining diseases, only for type 2 diabetes
does the genetic contribution of the genes with minor effects come
anywhere close to being of any public health significance (Dermitzakis
and Clark 2009; Manolio et al. 2009). In the case of AMD, the five genes
determine approximately half the predicted genetic risk (Maller et al.
2006). Apart from these, GWA studies have found little genetic variation
for disease. The few conclusive examples in which genes have a
significant predisposing influence on a common disease remain the gene
variant associated with Alzheimer’s disease and the breast cancer genes
BRCA1 and 2, all of which were discovered well before the GWA era (Miki
et al. 1994 and Reiman et al. 1996).
Though they have not found what their
designers hoped they would, the results of the GWA studies of common
diseases do support two distinct conclusions, both with far-reaching
implications. First, apart from the exceptions noted, the genetic
contribution to major diseases is small, accounting at most for around 5
or 10% of all disease cases (Manolio et al. 2009). Secondly, and
equally important, this genetic contribution is distributed among large
numbers of genes, each with only a minute effect (Hindorff et al. 2009).
For example, the human population contains at least 40 distinct genes
associated with type I diabetes (Barrett et al. 2009). Prostate cancer
is associated with 27 genes (Ioannidis et al. 2010); and Crohn’s disease
with 32 (Barrett et al. 2008).
The implications for understanding how
each person’s health is affected by their genetic inheritance are
remarkable. For each disease, even if a person was born with every known
‘bad’ (or ‘good’) genetic variant, which is statistically highly
unlikely, their probability of contracting the disease would still only
be minimally altered from the average.
Scientists Discover Quadruple Helix: Four Strand DNA In Human Cells
The human race knows very little of
itself, almost like a race with amnesia. As we continue to move forward
through time, new discoveries are made that make old theories obsolete
and false. It’s a good lesson that shows us how we can attach ourselves
to “truths” and believe them whole-heartedly, often forgetting that
truth is constantly changing and new paradigms of perception always lurk
around the corner.
Decades after scientists described our
“chemical code” of life using the double helix DNA, researchers have
discovered four-stranded DNA within human cells. The structures are
called G-quadruplexes, because they form in regions of DNA that are full
of guanine, one of the DNA molecule’s four building blocks. The others
are adenine, cytosine and thymine. A hydrogen bond is responsible for
holding the four guanines together. The four stranded DNA usually
presents itself right before cell division.
The discovery was published online in Nature Chemistry, and you can take a look at it here. The study was led by Shankar Balasubramanian at the University of cambridge, UK.
The Ghost in our Genes
(epigenetics)
(epigenetics)
Our genes carry unbelievable information
of our past. And it is this genetic information, that affects our
present, because the only way forward is to look into the past. This
documentary film explains genetic science and it’s impact on our future
life.
A gene is the basic unit of heredity in a living organism. The field
of genetics predates modern molecular biology, but it is now known that
all living things depend on DNA to pass on their traits to offspring.
Genetics is a discipline of biology and the science of heredity and
variation in living organisms. The fact that living things inherit
traits from their parents has been used since prehistoric times to
improve crop plants and animals through selective breeding.
However, the modern science of genetics,
which seeks to understand the process of inheritance, only began with
the work of Gregor Mendel in the mid-nineteenth century. Although he did
not know the physical basis for heredity, Mendel observed that
organisms inherit traits in a discrete manner-these basic units of
inheritance are now called genes.
Biology stands on the brink of a shift in the understanding of inheritance. The discovery of epigenetics — hidden influences upon the genes — could affect every aspect of our lives.
At the heart of this new field is a simple but contentious idea — that genes have a ‘memory’. That the lives of your grandparents — the air they breathed, the food they ate, even the things they saw — can directly affect you, decades later, despite your never experiencing these things yourself. And that what you do in your lifetime could in turn affect your grandchildren.
The conventional view is that DNA carries all our heritable information and that nothing an individual does in their lifetime will be biologically passed to their children. To many scientists, epigenetics amounts to a heresy, calling into question the accepted view of the DNA sequence — a cornerstone on which modern biology sits.
Epigenetics adds a whole new layer to genes beyond the DNA. It proposes a control system of ‘switches’ that turn genes on or off — and suggests that things people experience, like nutrition and stress, can control these switches and cause heritable effects in humans.
In a remote town in northern Sweden there is evidence for this radical idea. Lying in Överkalix’s parish registries of births and deaths and its detailed harvest records is a secret that confounds traditional scientific thinking. Marcus Pembrey, a Professor of Clinical Genetics at the Institute of Child Health in London, in collaboration with Swedish researcher Lars Olov Bygren, has found evidence in these records of an environmental effect being passed down the generations. They have shown that a famine at critical times in the lives of the grandparents can affect the life expectancy of the grandchildren. This is the first evidence that an environmental effect can be inherited in humans.
In other independent groups around the world, the first hints that there is more to inheritance than just the genes are coming to light. The mechanism by which this extraordinary discovery can be explained is starting to be revealed.
Professor Wolf Reik, at the Babraham Institute in Cambridge, has spent years studying this hidden ghost world. He has found that merely manipulating mice embryos is enough to set off ‘switches’ that turn genes on or off.
For mothers like Stephanie Mullins, who had her first child by in vitro fertilisation, this has profound implications. It means it is possible that the IVF procedure caused her son Ciaran to be born with Beckwith-Wiedemann Syndrome — a rare disorder linked to abnormal gene expression. It has been shown that babies conceived by IVF have a three- to four-fold increased chance of developing this condition.
And Reik’s work has gone further, showing that these switches themselves can be inherited. This means that a ‘memory’ of an event could be passed through generations. A simple environmental effect could switch genes on or off — and this change could be inherited.
His research has demonstrated that genes and the environment are not mutually exclusive but are inextricably intertwined, one affecting the other.
The idea that inheritance is not just about which genes you inherit but whether these are switched on or off is a whole new frontier in biology. It raises questions with huge implications, and means the search will be on to find what sort of environmental effects can affect these switches.
After the tragic events of September 11th 2001, Rachel Yehuda, a psychologist at the Mount Sinai School of Medicine in New York, studied the effects of stress on a group of women who were inside or near the World Trade Center and were pregnant at the time. Produced in conjunction with Jonathan Seckl, an Edinburgh doctor, her results suggest that stress effects can pass down generations. Meanwhile research at Washington State University points to toxic effects — like exposure to fungicides or pesticides — causing biological changes in rats that persist for at least four generations.
This work is at the forefront of a paradigm shift in scientific thinking. It will change the way the causes of disease are viewed, as well as the importance of lifestyles and family relationships. What people do no longer just affects themselves, but can determine the health of their children and grandchildren in decades to come. “We are,” as Marcus Pembrey says, “all guardians of our genome.”
Geen opmerkingen:
Een reactie posten