I just read on Vitisphere (my translation)

Pinot gris is a chimera

Research by INRA in Colmar on the pinot genome has led to an amazing
discovery: certain versions of the pinot gris grape have two distinct
genomes, one for the skin and one for the berry itself. In genetics
this is referred to as a "natural tissue chimera". So in pinot gris
one finds the skin genome, that gives it its colour and therefore its
aroma, and the denome of the interior tissues, which are IDENTICAL TO
PINOT BLANC ! The study encompassed 6 types of pinot : gris, noir,
meunier, teinturier, blanc and moure.


Mike

Mike Tommasi, Six Fours, France
email link http://www.tommasi.org/mymail

Mike Tommasi wrote:
> I just read on Vitisphere (my translation)
>
> Pinot gris is a chimera
>
> Research by INRA in Colmar on the pinot genome has led to an amazing
> discovery: certain versions of the pinot gris grape have two distinct
> genomes, one for the skin and one for the berry itself. In genetics
> this is referred to as a "natural tissue chimera". So in pinot gris
> one finds the skin genome, that gives it its colour and therefore its
> aroma, and the denome of the interior tissues, which are IDENTICAL TO
> PINOT BLANC ! The study encompassed 6 types of pinot : gris, noir,
> meunier, teinturier, blanc and moure.

Mike,
This is mind boggling if true: the genome of the skin tissue is
DIFFERENT from that of the flesh. That implies that either a mutation
takes place during the development of the grape, or that the skin and
the flesh are derived from two different germ lines. Neither
explanation makes much sense to me...

Mark Lipton

BTW, Googling for the phrase "natural tissue chimera" turned up nothing.

Mark Lipton wrote:
> Mike Tommasi wrote:
>
>> I just read on Vitisphere (my translation)
>>
>> Pinot gris is a chimera

> Mike,
> This is mind boggling if true: the genome of the skin tissue is
> DIFFERENT from that of the flesh. That implies that either a mutation
> takes place during the development of the grape, or that the skin and
> the flesh are derived from two different germ lines. Neither
> explanation makes much sense to me...

I'm not even remotely an expert in this field (my initial
exposure to the subject was an episode of CSI last year),
but I did a brief bit of web-research then, for what it's
worth. I was left with the impression that a chimera is the
result of a mutation or aberration in development; so I
too am quite surprised to find an example of something
that reliably reproduces as a chimera.

I'd think that the seeds would contain one genome or another.

Dana

On Fri, 18 Jun 2004 10:01:29 -0500, Mark Lipton >
wrote:

>Mike Tommasi wrote:
>> I just read on Vitisphere (my translation)
>>
>> Pinot gris is a chimera
>>
>> Research by INRA in Colmar on the pinot genome has led to an amazing
>> discovery: certain versions of the pinot gris grape have two distinct
>> genomes, one for the skin and one for the berry itself. In genetics
>> this is referred to as a "natural tissue chimera". So in pinot gris
>> one finds the skin genome, that gives it its colour and therefore its
>> aroma, and the denome of the interior tissues, which are IDENTICAL TO
>> PINOT BLANC ! The study encompassed 6 types of pinot : gris, noir,
>> meunier, teinturier, blanc and moure.
>
>Mike,
> This is mind boggling if true: the genome of the skin tissue is
>DIFFERENT from that of the flesh. That implies that either a mutation
>takes place during the development of the grape, or that the skin and
>the flesh are derived from two different germ lines. Neither
>explanation makes much sense to me...

Incidentally, I have heard that trees are often colonies of
individuals with different genetic codes. I never knew it could happen
within a fruit !

Mike

Mike Tommasi, Six Fours, France
email link http://www.tommasi.org/mymail

http://www.plosbiology.org/plosonlin...l.pbio.0020043


Mark Lipton wrote:
> Mike Tommasi wrote:
>
>> I just read on Vitisphere (my translation)
>>
>> Pinot gris is a chimera
>>
>> Research by INRA in Colmar on the pinot genome has led to an amazing
>> discovery: certain versions of the pinot gris grape have two distinct
>> genomes, one for the skin and one for the berry itself. In genetics
>> this is referred to as a "natural tissue chimera". So in pinot gris
>> one finds the skin genome, that gives it its colour and therefore its
>> aroma, and the denome of the interior tissues, which are IDENTICAL TO
>> PINOT BLANC ! The study encompassed 6 types of pinot : gris, noir,
>> meunier, teinturier, blanc and moure.
>
>
> Mike,
> This is mind boggling if true: the genome of the skin tissue is
> DIFFERENT from that of the flesh. That implies that either a mutation
> takes place during the development of the grape, or that the skin and
> the flesh are derived from two different germ lines. Neither
> explanation makes much sense to me...
>
> Mark Lipton
>
> BTW, Googling for the phrase "natural tissue chimera" turned up nothing.

Mike wrote:
> http://www.plosbiology.org/plosonlin...l.pbio.0020043

Most helpful, Mike. Although this particular effect seems specific to
the scale insects ("Obligate chimerism—the presence of two genetically
distinct cell lineages in every individual at each life stage—is found
in a few families of scale insects, but nowhere else in nature.") it did
lead me to the correct Google search, which turned up this reference:

http://www.actahort.org/books/603/603_70.htm

It seems that this effect occurs because the Pinot cultivars possess 3
instead of 2 copies of one chromosome, which permits one layer of cells
to use one version and another layer to use a different version. Not
only that, but if the two layers of cells are separated and allowed to
develop into grapes, both layers give rise to grapes that are distinct
from Pinot Gris:

http://tinyurl.com/2j3ey

Truth is stranger than fiction yet again!

Mark Lipton

"Mark Lipton" > wrote in message
...
> This is mind boggling if true: the genome of the skin tissue is
> DIFFERENT from that of the flesh. That implies that either a mutation
> takes place during the development of the grape, or that the skin and
> the flesh are derived from two different germ lines. Neither
> explanation makes much sense to me...
>
> Mark Lipton
>
> BTW, Googling for the phrase "natural tissue chimera" turned up nothing.

There was an episode of CSI recently where this phenomenon, although in a
_human_, was central to the story. The killer's DNA from a mouth swab was
different from the DNA in his blood (which was the same as found at the
crime scene). It stumped Grissom for a while, but he eventually figured it
out.

I wasn't sure this was a real phenomenon, but a Copernic search on
chimera+DNA turned up this link:
http://www.ananova.com/news/story/sm...ery.genet ics

It gets even weirder with this one:
http://www.nature.com/nsu/020429/020429-13.html which mentions a phenomenon
called mosaicism.

Tom S

"Dana Myers" > wrote in message
m...
> I'd think that the seeds would contain one genome or another.

They very well may, but grapevines are not replicated from seeds - at least
not in viticulture. They are cloned from cuttings. This is true of many
cultivated species for that matter (e.g. apples and roses) when genetic
diversity is _not_ desired.

Tom S

Tom S wrote:

> "Dana Myers" > wrote in message
> m...
>
>>I'd think that the seeds would contain one genome or another.
>
>
> They very well may, but grapevines are not replicated from seeds - at least
> not in viticulture. They are cloned from cuttings. This is true of many
> cultivated species for that matter (e.g. apples and roses) when genetic
> diversity is _not_ desired.

Right - I understand. However, I was thinking of how such a mutation would
occur and propagate in nature.

Dana

Dana Myers > wrote :

> Mark Lipton wrote:
> > Mike Tommasi wrote:
> >
> >> I just read on Vitisphere (my translation)
> >>
> >> Pinot gris is a chimera
>
> > Mike,
> > This is mind boggling if true: the genome of the skin tissue is
> > DIFFERENT from that of the flesh. That implies that either a mutation
> > takes place during the development of the grape, or that the skin and
> > the flesh are derived from two different germ lines. Neither
> > explanation makes much sense to me...
>
> I'm not even remotely an expert in this field (my initial
> exposure to the subject was an episode of CSI last year),
> but I did a brief bit of web-research then, for what it's
> worth. I was left with the impression that a chimera is the
> result of a mutation or aberration in development; so I
> too am quite surprised to find an example of something
> that reliably reproduces as a chimera.
>
> I'd think that the seeds would contain one genome or another.
>
> Dana

Right. But vines are propagated asexually, so a mutation can be
reproduced indefinitely. I think. I don't know much about the subject
either and I don't watch CSI, so you may have the advantage.

For french readers, a more complete article straight from INRA

http://www.inra.fr/presse/mai04/nb1.html



Mike Tommasi, Six Fours, France
email link http://www.tommasi.org/mymail