See also Carl Zimmer’s essay: “Us and them among the slime molds”
“Tight-knit family: Even microbes favour their own kin”
New research published by Rice University biologists in this week’s issue of Nature finds that even the simplest of social creatures – single-celled amoebae – have the ability not only to recognize their own family members but also to selectively discriminate in favour of them.
Development of slime mold, Dictyostelium
(Credit: M. Grimson, R. Blanton)
“The new study is based on an examination of single-celled Dictyostelium purpureum, a common soil microbe that feeds on bacteria. In the wild, when food runs short, D. purpureum aggregate together by the thousands, forming first into long narrow slugs [slime molds] and then into hair-like fruiting bodies. Resembling miniature mushrooms, these fruiting bodies consist of both a freestanding stalk and the spores that sit atop it… In order to disperse the spores, some of the colony’s individuals must altruistically sacrifice themselves in order to make the stalk.”
The researchers found that if millions of individual amoebae from two different isolates were mixed, when they used up their food and started to seek each other out, then in any given stalk almost all the cells came from one isolate or the other. This showed that relatives were seeking each other out — and is one of the first studies to document the trait of kin discrimination in a social microorganism.
A Dictysotelium purpureum fruiting body
(Credit: Owen Gilbert/Rice University)
PS. This is a rather wordy review. If I can get my brain out of sluggish mode I’ll tidy it up…