nafex@lists.ibiblio.org
Subject: North American Fruit Explorers mailing list at ibiblio
List archive
- From: "Stephen Sadler" <Docshiva@Docshiva.org>
- To: "'North American Fruit Explorers'" <nafex@lists.ibiblio.org>
- Subject: RE: [NAFEX] candid chimera
- Date: Thu, 17 Feb 2005 13:00:41 -0800
Chimeras occur in mammals when the mother produces two fetuses which fuse in
utero. This happens with some frequency in cattle, but I know of no cases
in humans, though it's theoretically possible.
There is another condition where cells arising from one zygote can have
slightly different genetics. This is called mosaicism. In mosaicism, the
gene expressions of some cells is suppressed. For example, in female
mammals, all but one X chromosome is inactivated early in development. Half
of those X chromosomes inactivated will have been paternally inherited, and
half maternally inherited - so there is some genetic difference, or a type
of mosaicism, present in female mammals. Different types of mosaicism are
fairly common in animals.
One type suppresses some of genes responsible for eye color in some cells;
so some cells that develop into an iris will have switched-on instructions
for blue eyes, and others will have active instructions for making brown
eyes. This is the same type of mechanism which causes calico in cats.
As far as how chimeras occur in plants, please look at Lee's explanation.
It doesn't happen in one individual organism - it requires a fusion of two.
Mosaicism arises from a single seed or zygote.
Stephen Sadler, Ph.D.
USDA 9, AHS heat zone 8,
Sacramento CA - Mediterranean climate
>
I wasn't familiar with this term used in a botanical sense,
so I looked it up and found:
"an individual, organ, or part consisting of tissues of
diverse genetic constitution"
Would a person with one blue eye and one brown eye be
considered a 'chimera' in this sense of the term?
*Why* would this happen within an individual organism, such
as one apple tree or one tomato plant?
Pat
-
Re: [NAFEX] aronia rootstock
, (continued)
-
Re: [NAFEX] aronia rootstock,
rob hamilton, 02/16/2005
- Re: [NAFEX] aronia rootstock, John Smith, 02/16/2005
-
RE: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
Stephen Sadler, 02/16/2005
- Re: [NAFEX] It doesn't take a genus to see that there must be some relationship..., Lon Rombough, 02/16/2005
-
RE: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
John Smith, 02/16/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
Lon Rombough, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
lee reich, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
rob hamilton, 02/17/2005
- Re: [NAFEX] It doesn't take a genus to see that there must be some relationship..., lee reich, 02/17/2005
- Re: [NAFEX] It doesn't take a genus to see that there must be some relationship..., Pat Meadows, 02/17/2005
- RE: [NAFEX] candid chimera, Stephen Sadler, 02/17/2005
- [NAFEX] chimera, Lucky Pittman, 02/17/2005
- Re: [NAFEX] It doesn't take a genus to see that there must be some relationship..., rob hamilton, 02/17/2005
- RE: [NAFEX] sports, Stephen Sadler, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
rob hamilton, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
lee reich, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be some relationship...,
Lon Rombough, 02/17/2005
-
RE: [NAFEX] It doesn't take a genus to see that there must be somerelationship...,
Mark Lee, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be somerelationship...,
Lon Rombough, 02/17/2005
- RE: [NAFEX] It doesn't take a genus to see that there must besomerelationship..., Mark Lee, 02/17/2005
- Re: [NAFEX] It doesn't take a genus to see that there must besomerelationship..., Lon Rombough, 02/17/2005
-
Re: [NAFEX] It doesn't take a genus to see that there must be somerelationship...,
Lon Rombough, 02/17/2005
-
Re: [NAFEX] aronia rootstock,
rob hamilton, 02/16/2005
Archive powered by MHonArc 2.6.24.