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Author Topic: Does a multicellular organism have to consist of genetically compatible cells?  (Read 3303 times)

Offline Promilla

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I am wondering, would it be possible for a multicellular organism to consist of genetically different cells. As for now we know that all cells in out body have the same genetic information, but different expression of genes. But I am wondering, is it possible for an organism to have cells with different genetic information? And if not, why is that?


 

Offline RD

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« Last Edit: 07/12/2014 17:08:16 by RD »
 

Offline CliffordK

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There are also many examples of symbiosis on Earth.

For example the Lichen which is a type of symbiosis between a fungus and cyanobacteria.

Legumes also have a symbiotic relationship between plant and rhizobia bacteria for nitrogen fixation. 

Even humans have developed a symbiotic relationship with a diverse collection of bacteria and yeast known collectively as flora. 

Every Eukaryote cell (plants, animals) have either mitochondria or chloroplasts which are essentially genetically distinct inclusions from the rest of the cells.  Current cloning techniques usually preserve the mitochondria from the donor egg, and only add nuclear DNA from the organism being cloned.
 

Offline Promilla

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Cool. Thank you very much for your answers! They are really interesting. CliffordK so would you say that symbiotic organisms could be by some criteria considered one organism? I guess it's a matter of definition of what is considered one organism, isn't it? Could you consider for example a human being with all its microorganisms one organism, since there is beneficial relationship for both of them?
 

Offline CliffordK

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I think I would consider a Lichen as a single organism, although potentially the cyanobacteria and funghi could be separated, or recombined with different lichens.  I don't know if either organism is viable on its own...  or viable outside of a lab on its own as I assume each type of lichen has evolved together.

Likewise, I think I would consider a pea as a single organism, but that may be a little more loose of a symbiotic relationship. 

Humans, and our flora?...  I don't know.

As far as Nuclear DNA vs Chloroplasts and Mitochondria.  That definitely fits under a single organism.
 

Offline cheryl j

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Well for at least nine months, you can be pretty genetically different. Granted there's an interface like the placenta to help prevent immunological attack, but hosting a baby is still pretty impressive biologically.

I haven't seen anything lately, but a year or so ago there were articles about occasionally fetal cells could be found in the mother's organs, such as the liver, years and years later. I don't know if that research was ever replicated.
 

Offline evan_au

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Quote from: cheryl j
occasionally fetal cells could be found in the mother's organs

It's called "microchimerism", and is fairly well established.
It is more controversial as to whether microchimerism contributes to auto-immune diseases, which are more common in women.
 

Offline evan_au

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Corals obtain their color from genetically distinct  zooxanthellae living within their cells.
Under excessive temperature events, the coral can expel their zooxanthellae, resulting in coral bleaching.
It seems that at least in some cases, the coral organism can survive the loss of their symbionts, and be recolonised later.

I guess that "independent living" is a significant characteristic:
  • Coral and zooxanthellae can live independently
  • Humans can survive after their gut bacteria have been killed
  • Humans and mitochondria cannot survive independently - they are too interdependent
  • Plants and chloroplasts cannot survive independently - they are too interdependent 
 

Offline cheryl j

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Quote from: cheryl j
occasionally fetal cells could be found in the mother's organs

It's called "microchimerism", and is fairly well established.
It is more controversial as to whether microchimerism contributes to auto-immune diseases, which are more common in women.

The article I recall reading mentioned autoimmune disease, but was also about investigating whether such cells had any positive benefit, as they seemed to take up residence in damaged tissue - like the liver. I thought that was kind of interesting.
 

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