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Science Forum Index » Bio Evolution Forum » "Identical" twins not genetically identical
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| Tim Tyler |
 Posted: Fri Feb 22, 2008 8:49 am |
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``Contrary to our previous beliefs, identical twins are not
genetically identical. This surprising finding may be of
great significance for research on hereditary diseases
and for the development of new diagnostic methods. How
can it be that one identical twin might develop Parkinson's
disease, for instance, but not the other? Until now, the
reasons have been sought in environmental factors. The
current study complicates the picture.''
- http://www.sciencedaily.com/releases/2008/02/080215121214.htm
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|im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply. |
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| Tom Hendricks |
| Posted: Tue Feb 26, 2008 8:44 am |
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On Feb 22, 12:49 pm, Tim Tyler <seemy...@cyberspace.org> wrote:
Quote: ``Contrary to our previous beliefs, identical twins are not
genetically identical. This surprising finding may be of
great significance for research on hereditary diseases
and for the development of new diagnostic methods. How
can it be that one identical twin might develop Parkinson's
disease, for instance, but not the other? Until now, the
reasons have been sought in environmental factors. The
current study complicates the picture.''
-http://www.sciencedaily.com/releases/2008/02/080215121214.htm
--
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|im |yler http://timtyler.org/ t...@tt1lock.org Remove lock to reply.
I always thought that cloning would prove or disprove astrology.
Same genes, but different birth dates. We in our smug science world
might have to see identical twins as being born under different stars
(ever so slight different stars) and that makes all the difference. |
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| Perplexed in Peoria |
| Posted: Tue Feb 26, 2008 8:44 am |
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"Tim Tyler" <seemysig@cyberspace.org> wrote in message news:fpn5fd$jmm$1@darwin.ediacara.org...
Quote: ``Contrary to our previous beliefs, identical twins are not
genetically identical. This surprising finding may be of
great significance for research on hereditary diseases
and for the development of new diagnostic methods. How
can it be that one identical twin might develop Parkinson's
disease, for instance, but not the other? Until now, the
reasons have been sought in environmental factors. The
current study complicates the picture.''
- http://www.sciencedaily.com/releases/2008/02/080215121214.htm
From the article:
The researchers studied 19 pairs of monozygotic, or identical,
twins and found differences in copy number variation in DNA.
Copy number variation (CNV) occurs when a set of coding
letters in DNA are missing, or when extra copies of segments
of DNA are produced.
I would think that there would be copy-number variation among
the somatic cells of a single individual. Finding it in MZ twins
therefore doesn't strike me as especially surprising. |
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| Tim Tyler |
| Posted: Tue Feb 26, 2008 8:24 pm |
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Perplexed in Peoria wrote:
Quote: I would think that there would be copy-number variation among
the somatic cells of a single individual. Finding it in MZ twins
therefore doesn't strike me as especially surprising.
The paper says:
``Somatic mosaicism is usually defined by the presence of
genetically distinct populations of somatic cells in a
single organism. Any genetic difference between MZ twins
represents an extreme example of somatic mosaicism.''
.....and:
``This steadily growing body of data indicates that
somatic mosaicism for pathogenic mutations affecting
known disease genes might be seen as a rule rather
than as an exception. In addition, it was recently
demonstrated that the frequency of inversions is
altered between different populations of normal
somatic cells in a healthy subject. However,
the frequency of in vivo somatic mosaicism for
copy-number variations (CNVs) in populations
of apparently normal cells is so far unexplored.''
- Phenotypically Concordant and Discordant
Monozygotic Twins Display Different
DNA Copy-Number-Variation Profiles
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|im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply. |
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| DK |
| Posted: Tue Feb 26, 2008 8:24 pm |
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In article <fpn5fd$jmm$1@darwin.ediacara.org>, Tim Tyler <seemysig@cyberspace.org> wrote:
Quote: ``Contrary to our previous beliefs, identical twins are not
genetically identical. This surprising finding may be of
great significance for research on hereditary diseases
and for the development of new diagnostic methods. How
can it be that one identical twin might develop Parkinson's
disease, for instance, but not the other? Until now, the
reasons have been sought in environmental factors. The
current study complicates the picture.''
- http://www.sciencedaily.com/releases/2008/02/080215121214.htm
Papers describing epigenetic differences between identical
tweens date back at least 6 years ago... |
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| Tim Tyler |
| Posted: Wed Feb 27, 2008 8:47 am |
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DK wrote:
Quote: In article <fpn5fd$jmm$1@darwin.ediacara.org>, Tim Tyler <seemysig@cyberspace.org> wrote:
``Contrary to our previous beliefs, identical twins are not
genetically identical. This surprising finding may be of
great significance for research on hereditary diseases
and for the development of new diagnostic methods. How
can it be that one identical twin might develop Parkinson's
disease, for instance, but not the other? Until now, the
reasons have been sought in environmental factors. The
current study complicates the picture.''
- http://www.sciencedaily.com/releases/2008/02/080215121214.htm
Papers describing epigenetic differences between identical
tweens date back at least 6 years ago...
This is "epigenetic" in the sense of the Russo, Martienssen, Riggs
(1992) attempt to redefine the word, I presume.
I haven't heard about those.
Otherwise, the papers date back a /lot/ longer than six years.
--
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|im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply. |
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