Is this Evidence of Evolution in a SIngle Generation?

a reply to: Slanter

Yes, I believe so

a reply to: OccamsRazor04

I don't think I understand your question.

There's most likely some competition due to overcrowding, but no predation that I know of.

This an interesting paper. I threw together a little graphic that shows the how the sample fish were derived.

click image for larger view

It's interesting to see how these epigenetic changes occurred so quickly. It's almost as if there were some program activated by their confinement in the alternative environment of the Hatchery.

I remember recently reading about some crickets in the Hawaiian Islands that had evolved over the course of a few generations to foil the hunting practices of one of their predators. However, I believe those changes were genetics rather than epigenetic. I don't know whether that was ever discussed here on ATS.

-dex

originally posted by: PhotonEffect
a reply to: chr0naut

I tend to agree with you on all points.

But let's shelve the cynicism for a minute and assume that the researchers were not compromised and their results are true. Can it be considered, by the current definition, to be evolution (in one generation)?

Also, to be published in Nature, it would have to be peer reviewed, yes?

I think this is indicative of a short-fall in the scope of evolution. I can think of no other source of the gene changes except for epigenetics but the changes as suggested may have been evolved to deal with overcrowding situations.

Evolutionary forces implicitly cover vast swathes of time but life is violent and has to cope with whatever situations and chance throws at it and the reality is that change is the only constant that we could reliably expect.

Consider this scenario; Salmon live in rivers which can run dry according to weather conditions and causing overcrowding. Drying up rivers are only a seasonal problem but the population that survives overcrowding effectively will live to bloom in boom times. So the species with epigenetic triggers that respond to overcrowding wins over the species that has 'evolved' for a static environment (that doesn't actually exist).

That is exactly what I suspect is occurring here. As such, this ISevolution but like a maestro performance has taken a lot of preparation to carry off. It does not, however, conform to the reductionist and simplistic model/s of evolution that are currently defined.

I suppose the stresses of the parent generation could affect the gene expression seen in the offspring. However I suppose this would also imply that most of the genes were already there before the conditions (more cramped and less selection of breeding partners) and horomone responses that may be affecting this kind of adaptation and particular type of speciation. At this stage though, it might be more akin to making different breeds of fish via domestication than outright incompatible species. (Like wolves vs. dogs. Considered different and lots of trait variation, but still able to interbreed and have viable offspring.)

I suspect nature still has a few more tricks we can learn from. Particularly now that we can look at the code and compare from the very start of the process.

originally posted by: chr0naut

I think this is indicative of a short-fall in the scope of evolution. I can think of no other source of the gene changes except for epigenetics but the changes as suggested may have been evolved to deal with overcrowding situations.

It does seem that way.

Almost as a type of phenotypic plasticity

originally posted by: DexterRiley
I remember recently reading about some crickets in the Hawaiian Islands that had evolved over the course of a few generations to foil the hunting practices of one of their predators. However, I believe those changes were genetics rather than epigenetic. I don't know whether that was ever discussed here on ATS.

This sounds like a study that was done not too long ago about the green anole's rather quick (in 20 generations) evolution of their toe pads. Essentially they evolved to become larger and stickier to allow them climb higher up into the canopies, due to the invasion of the brown anole, which took over the lower areas.

www.sciencenews.org...

a reply to: PhotonEffect

I'm curious how it can be "evolution"? Did the fish change species? Did they start to breath air? Oh, a missing fin.... Looks like a gene mutation at best.

a reply to: jjkenobi

The phenotypic changes were adaptive, that resulted from over 700 genetic differences from the wild generation.

Does the study cite genetic mutations as the cause? If so, I missed it.

What I glean from this is that it was expression related, thus epigenetic in nature