The Raelian Movement
for those who are not afraid of the future : http://www.rael.org
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Finding Variants in the Human Genome: HapMap 3 Points the Way Forward
for Human Genetics Studies
http://www.sciencedaily.com/releases/2010/09/100901132201.htm
ScienceDaily (Sep. 1, 2010) — New findings show the value of genetic
studies across human populations and the value of the latest DNA
sequencing technologies to interrogate genetic variation. The results,
from the latest phase of the international HapMap Project, are
reported in Nature.
The researchers' extensive study of genetic variation in multiple
populations will form a framework for future genetic studies of
variation and disease: their findings highlight the need to examine
various populations in order to tease out the widest collection of
genetic variants, as well as the requirement to deploy sequencing
technologies to find as many variants as possible.
The HapMap Project seeks to identify signposts on the human genome
that will simplify the search for important genetic variants. In the
latest phase -- HapMap 3 -- the researchers looked for variants across
the genome in 1184 samples from 11 populations. They chose the large
sample set and the wide range of populations to maximize the variation
they could capture. The project includes both single-letter
differences (single-letter polymorphisms, or SNPs) as well as large
differences from the loss, gain or duplication of regions, called
copy-number polymorphisms, or CNPs.
"Despite the remarkable achievements following from the Human Genome
Project, our knowledge of human genetic variation remains limited,"
says Professor Richard Gibbs, professor of molecular and human
genetics at Baylor College of Medicine in Houston, Texas, and director
of the BCM Human Genome Research Center. "Here we have studied more
populations and were able to include CNPs in genomewide studies.
"These results tell us more about human genetic variation and about
how to study variation successfully."
The results show that rarer variants are distributed more unevenly
among populations. This might be expected -- evolutionary theory
implies that the common variants are generally the older ones, having
had greater time to spread through a population -- but also cautions
that genetic studies should include a wide range of population groups
to maximise discovery of more recent, population-specific variants.
"The closer we look at human genetic variation, the greater the
granularity," explains Professor Manolis Dermitzakis, from the
University of Geneva and one of the project coordinators, and formerly
at the Wellcome Trust Sanger Institute. "An important task in genetics
is to discriminate between the variants that are important for health
and those that are part of the background.
"This new version of the HapMap will help us design ways to do that --
to sort the wheat from the chaff."
In addition to the genotyping studies described above, HapMap 3 also
sequenced ten segments of 100,000 bases from well-characterized
regions of the human genome. Unlike discovery using DNA chips -- as
used in most studies to date -- direct sequencing is not biased
towards more common variants, but gives a direct estimate of the
frequencies of variants.
The researchers found that most variants were relatively uncommon
(found in less than one person in ten), but they also found a large
number of rare variants (each found in less than one in 100 people) or
'private' variants (found in only one person). Almost eight of ten
variants were new and almost four of ten of those seen in less than
one in 100 people were found in only one population.
From the results, the researchers suggest that variants in some genes,
including genes involved in the immune system, wound healing and sense
of smell, are under selection in different populations. These genes
can now be studied to learn about how these systems work and about
disease resistance. These findings show the value of having large
studies that include many populations and samples to achieve
comprehensive understanding of human variation.
"Some have talked about how little has come from the Human Genome
Project over the past ten years, but perhaps they forget how little we
knew then," says Professor David Altshuler of Massachusetts General
Hospital in Boston and the Broad Institute of Massachusetts Institute
of Technology (MIT) and Harvard University in Cambridge, Mass. "It is
amazing that we have gone from a genome less than 90 per cent
completed to looking at genetic changes in one in 200 people or rarer.
A few years ago, we had no idea of the extent of structural variation
or how we might sample variants present at low frequency.
"The HapMap and other large-scale projects have transformed our
understanding of the human genome and its relation to health and
disease."
The HapMap 3/ENCODE 3 data set is publicly available at http://www.hapmap.org.
Story Source:
The above story is reprinted (with editorial adaptations by
ScienceDaily staff) from materials provided by Wellcome Trust Sanger
Institute.
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"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
There is nothing glorious about what our ancestors call history,
it is simply a succession of mistakes, intolerances and violations.
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
Rael
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