5 ms·

Was this completely new, or was it some sort of latent ability that was brought out by environmental conditioning?

by learc83 15y ago

ars 15y ago
It was a latent ability. Some yeast already has the ability to make multi cellular colonies. When this was first published (on June 23 - not sure why it's back in the news) there was a section of criticism saying they should have used an organism without that ability. But I don't see this section in the wired article. For example: http://blogs.discovermagazine.com/80beats/2011/06/23/yeast-can-evolve-into-multicellular-organisms-in-a-few-short-months/ http://blogs.discovermagazine.com/80beats/2011/06/23/yeast-c... http://www.sciencenews.org/view/generic/id/331789/title/Multicellular_life_arises_in_a_test_tube http://www.sciencenews.org/view/generic/id/331789/title/Mult...
- snippyhollow 15y ago
  It is back on the news because: “Experimental evolution of multicellularity.” By William C. Ratcliff, R. Ford Denison, Mark Borrello, and Michael Travisano. Proceedings of the National Academy of Sciences, Jan. 17, 2012.
- tylerritchie 15y ago
  >... not sure why it's back in the news ... The paper [1] was just published, the first round in the news was due to the presentation of their findings, but not the publishing of any papers (as near as I can tell). Thankfully it's an open-access article. [1] http://dx.doi.org/10.1073/pnas.1115323109 http://dx.doi.org/10.1073/pnas.1115323109
- lusr 15y ago
  I didn't quite know how to interpret "latent ability". Reading the article, apparently yeast used to be multicellular, which is a pretty valid criticism of this experiment having meaningful results in terms of how single-celled organisms evolved into multicelluar organisms.
  - padobson 15y ago
    This comment seems to assume that evolution can only go in one direction - from simple forms of life to more complex ones. If a complex form of life evolves to become simpler and then evolves again to become more complex, then there's just as much to be learned from following a line of evolution that increases complexity.
    - lusr 15y ago
      You are absolutely correct, and it's a comment I anticipated, which is why I qualified my original statement: "meaningful results _in terms of_ how single-celled organisms evolved into multicelluar organisms". (Although in fairness, it probably gives a hint and will certainly lead to future experiments that may provide the beginnings of an answer.)
    - ars 15y ago
      If you look at those "simpler" forms of life you find that the genes are not gone, but rather they are disabled. An example is Neoteny - the genes for adult forms are still there, but are unused. That's why I don't think much of this experiment - I bet the genes for multi cellular life were already there, and just needed reactivation - which happened randomly (perhaps due to environment, or perhaps they always activate, but just for short times, and this experiment selected for those with the longest or easiest to trigger activation), but no new genes were needed. To do this experiment properly do a DNA sequencing of the original and final forms. And I'm actually quite surprised that they didn't do that - wouldn't it be very useful to know which genes create multi cellular life? But I bet the genetic diff between them is tiny - just enough to activate genes that are already there in the starting yeast.
      - ZenPsycho 15y ago
        DNA isn't quite exactly like a program that you compile into a living organism. The conditions for its reproduction and expression are partially determined by its environment- so a shift from single celled from multi-celled life might not be able to be pinned on any particular gene or set of genes as a direct cause. You might end up with what is essentially the same sequence, with different parts now triggered by a slightly different proportion of a particular protein present within the cellular membrane.
nickpinkston 15y ago
I know this type of Amoeba had a "slug" state that it can form - so it's possible for sure the similar genes are there already too. http://en.wikipedia.org/wiki/Dictyostelid http://en.wikipedia.org/wiki/Dictyostelid

Was this completely new, or was it some sort of latent ability that was brought out by environmental conditioning?

by learc83 15y ago

Was this completely new, or was it some sort of latent ability that was brought out by environmental conditioning?

ars 15y ago

It was a latent ability. Some yeast already has the ability to make multi cellular colonies. When this was first published (on June 23 - not sure why it's back in the news) there was a section of criticism saying they should have used an organism without that ability. But I don't see this section in the wired article. For example: http://blogs.discovermagazine.com/80beats/2011/06/23/yeast-can-evolve-into-multicellular-organisms-in-a-few-short-months/ http://blogs.discovermagazine.com/80beats/2011/06/23/yeast-c... http://www.sciencenews.org/view/generic/id/331789/title/Multicellular_life_arises_in_a_test_tube http://www.sciencenews.org/view/generic/id/331789/title/Mult...

snippyhollow 15y ago
It is back on the news because: “Experimental evolution of multicellularity.” By William C. Ratcliff, R. Ford Denison, Mark Borrello, and Michael Travisano. Proceedings of the National Academy of Sciences, Jan. 17, 2012.
tylerritchie 15y ago
>... not sure why it's back in the news ... The paper [1] was just published, the first round in the news was due to the presentation of their findings, but not the publishing of any papers (as near as I can tell). Thankfully it's an open-access article. [1] http://dx.doi.org/10.1073/pnas.1115323109 http://dx.doi.org/10.1073/pnas.1115323109
lusr 15y ago
I didn't quite know how to interpret "latent ability". Reading the article, apparently yeast used to be multicellular, which is a pretty valid criticism of this experiment having meaningful results in terms of how single-celled organisms evolved into multicelluar organisms.
- padobson 15y ago
  This comment seems to assume that evolution can only go in one direction - from simple forms of life to more complex ones. If a complex form of life evolves to become simpler and then evolves again to become more complex, then there's just as much to be learned from following a line of evolution that increases complexity.
  - lusr 15y ago
    You are absolutely correct, and it's a comment I anticipated, which is why I qualified my original statement: "meaningful results _in terms of_ how single-celled organisms evolved into multicelluar organisms". (Although in fairness, it probably gives a hint and will certainly lead to future experiments that may provide the beginnings of an answer.)
  - ars 15y ago
    If you look at those "simpler" forms of life you find that the genes are not gone, but rather they are disabled. An example is Neoteny - the genes for adult forms are still there, but are unused. That's why I don't think much of this experiment - I bet the genes for multi cellular life were already there, and just needed reactivation - which happened randomly (perhaps due to environment, or perhaps they always activate, but just for short times, and this experiment selected for those with the longest or easiest to trigger activation), but no new genes were needed. To do this experiment properly do a DNA sequencing of the original and final forms. And I'm actually quite surprised that they didn't do that - wouldn't it be very useful to know which genes create multi cellular life? But I bet the genetic diff between them is tiny - just enough to activate genes that are already there in the starting yeast.
    - ZenPsycho 15y ago
      DNA isn't quite exactly like a program that you compile into a living organism. The conditions for its reproduction and expression are partially determined by its environment- so a shift from single celled from multi-celled life might not be able to be pinned on any particular gene or set of genes as a direct cause. You might end up with what is essentially the same sequence, with different parts now triggered by a slightly different proportion of a particular protein present within the cellular membrane.

nickpinkston 15y ago

I know this type of Amoeba had a "slug" state that it can form - so it's possible for sure the similar genes are there already too. http://en.wikipedia.org/wiki/Dictyostelid http://en.wikipedia.org/wiki/Dictyostelid