Can Directed Evolution Create Enhanced Cellular Traits?

[solitude]

How viable is this procedure: in order to create a desired genetic trait in a cell, one could subject cells to conditions such that without the trait they would die, to be performed until living cells are found? Would it be realistic to create new and improved cells by such a process? Why/why not? At what level of organization would this work (if at all, i.e. cellular, tissue**)? Once an improved cell has been isolated, what could one do to make the change pervade throughout an organism?

**It seems like in many environments such that cells would die without a certain trait, parts of the cells would inevitably get damaged even in surviving mutated cells. Perhaps then this procedure would work best at a particular organizational level to minimize collateral, such as the organelle level?

 

[Ygggdrasil]

Yes, this is how directed evolution experiments generally work. These are usually done at the cellular level.
http://en.wikipedia.org/wiki/Directed_evolution

 

[atyy]

Various variants of this idea are standard.

It is used, for example, in creating knock-out mice. http://www.bio.davidson.edu/courses/genomics/method/homolrecomb.html

Or to find genes that a bacterium needs to survive in a host. http://www.pnas.org/content/104/14/6037.abstract

 

[Ryan_m_b]

Once an improved cell has been isolated, what could one do to make the change pervade throughout an organism?

This is not possible; there exists no mechanism in human biology in which cells can swap genetic information. Some similar uses could be to genetically modify a progenitor cell that would then give rise to cells with the new genes (this might be particularly useful for genetic disorders) or to modify immune cells to recognise cancer.

 

[Tea Jay]

This is not possible; there exists no mechanism in human biology in which cells can swap genetic information. Some similar uses could be to genetically modify a progenitor cell that would then give rise to cells with the new genes (this might be particularly useful for genetic disorders) or to modify immune cells to recognise cancer.

Would using a virus count, or a bacterium with plasmids?

For human swaps, the 'ol double helix seems to do the trick?

It depends on the scale and time frame as to if you can take a cell with a trait, and "pass it on"

 

[Ryan_m_b]

Would using a virus count, or a bacterium with plasmids?

For human swaps, the 'ol double helix seems to do the trick?

It depends on the scale and time frame as to if you can take a cell with a trait, and "pass it on"

That isn't what the OP is talking about The OP outlined an idea of taking cells from an organism, subjecting them to directed evolution and then introducing the new cells back into the organism and expecting the trait to spread to the whole organism.

This could not occur, firstly the idea of taking human cells and getting them to evolve is faced with huge problems (like how you get the cells to proliferate for so many generations without making turning them cancerous) and secondly because there is no mechanism in human biology that allows for cells to simply swap DNA and spread new traits around the body.

 

[Ygggdrasil]

One way to get changes from a directed evolution experiment into an entire organism would be to either perform the directed evolution in stem cells or convert the evolved cells into stem cells. This is similar to how knock-out mice are made.

You would not be able to get t the trait into an existing organism for the reasons outlined by Ryan, but doing so would allow you to create a new organism with the evolved traits.

 

[Ryan_m_b]

One way to get changes from a directed evolution experiment into an entire organism would be to either perform the directed evolution in stem cells or convert the evolved cells into stem cells. This is similar to how knock-out mice are made.

Yup...

This is not possible; there exists no mechanism in human biology in which cells can swap genetic information. Some similar uses could be to genetically modify a progenitor cell that would then give rise to cells with the new genes (this might be particularly useful for genetic disorders) or to modify immune cells to recognise cancer.

 

[atyy]

... modify immune cells to recognise cancer.

Any pointers for reading about the current state of this technology?

 

[Ygggdrasil]

I'm on my phone right now so I can't get to the article, but here's the best link I could find (which at least has the citation in the bottom right corner):
http://xkcd.com/938/

 

[Ryan_m_b]

I'm also on my phone so it's hard to get links but here is a research group from my old university that specialised in this research
http://www.ucl.ac.uk/cancer/reshaematology/tumorimm

 

[Major Lazer]

Well it depends on what type of immune cells you are attempting to modify. I am currently rotating in a lab that specializes in adoptive T cell therapy for use in cancer treatments. If you want a good place to start (after an immunology textbook) would be review papers by Carl H. June, they are fairly recent. I just assigned to read them by my P.I. myself, so hope they are still somewhat relevant!

Priciples of Adoptive T Cell Cancer Therapy. Carl H. June, May 2007

and

Adoptive T Cell Therapy for Cancer in the Clinic. Carl H. June, June 2007

Robert Worthen
Dartmouth MCB Graduate Program

 

[atyy]

@Ygggdrasil

@Ryan_m_b and Major Lazer: thanks for the references!