Comments on: Green beards, flocs of yeast and the evolution of cooperation

By: Why Bugs Bite the Bullet for Brothers | Big Ten Science

Why Bugs Bite the Bullet for Brothers | Big Ten Science — Tue, 28 Sep 2010 15:06:56 +0000

[...] True, it hasn’t been shown in mammals, but it has appeared in the slime mold Dictyostelium, certain types of yeast, a bacterial plant pathogen and the side-blotched [...]

By: David Harmon

David Harmon — Sun, 16 Nov 2008 21:38:04 +0000

I seem to recall hearing about another “green beard” gene (described as such) in slime molds, critical for their forming of fruiting bodies. IIRC, the cells showed a similar pattern of excluding non-carriers from the spore case.

By: toto

toto — Sun, 16 Nov 2008 13:04:40 +0000

Additionally, this shows how “green beard” genes can be extremely simple both in form and function. Green beard genes often seem unlikely to the novice, since they seem to involve rather complex machinery (signalling and recognition) being packed in the same gene. This is a clear example that both signalling and recognition can be achieved by one simple trait.

By: galapagos

galapagos — Sun, 16 Nov 2008 02:15:24 +0000

Just wanted to say thanks for the good read as usual, and make sure someone commented on the clever photoshop. I chuckled. Keep it up!

By: Ed Yong

Ed Yong — Sat, 15 Nov 2008 11:19:51 +0000

Thanks nitpickers one and all.
Arensb – just one detail: I think the sticky protein sticks to another molecule on the cell wall rather than itself. I think the point is that if two cells are sticking to each other with the protein, the bond between them is stronger than if just one cell was doing it.

By: arensb

arensb — Sat, 15 Nov 2008 08:18:14 +0000

Another nit to pick: “Smukalla put the different strains through the ringer” should read “…through the wringer”. I believe this refers to old-style clothes wringers, which pressed clothes between two rollers to squeeze out the water after they had been laundered.
Other than that, it’s an interesting result. While reading the post, I was wondering how a single gene could cause such “green beard” behavior, and imagined a protein sticking out of the cell wall, with an end that sticks well to other copies of itself. And lo and behold, I was right.

By: Robert V Sobczak

Robert V Sobczak — Sat, 15 Nov 2008 03:22:39 +0000

Cooperation is a tricky word … we struggle as much with the language as we do with the science. Language is sometimes a blunter instrument that we like to admit.

By: Ford

Ford — Fri, 14 Nov 2008 23:13:36 +0000

Microbes can certainly cooperate, but sticking to other cells may not qualify as cooperation, if any benefits to OTHER cells are unselected side-effects. West et al. have defined cooperation as “a behaviour which provides a benefit to another individual (recipient), AND which is selected for because of its beneficial effect on the recipient.” This sounds like it could be more of a “selfish herd” effect; see John Dennehy’s blog of a few months ago on the classic paper by that name.

By: Hank Campbell

Hank Campbell — Fri, 14 Nov 2008 23:09:14 +0000

So FLO1 positive cells stick together, teaching us nice things about evolution, AND we get optimized beer?
This is the most important science article I will read this week.

By: jj

jj — Fri, 14 Nov 2008 16:48:45 +0000

correction
“Brewers add oxygen to their fermented brew” should read
“Brewers add oxygen to their unfermented brew”