Environment and Gene Expression

[amtiskaw]

I just read an interesting article on how environmental factors actually regulate gene expression. It's mostly discussing experiments with bees, but this one paragraph about cichlids might be of interest to fellow fish fanciers. :dunno:

"One of the most startling early demonstrations of such a response occurred in 2005 in the lab of Stanford biologist Russell Fernald. For years, Fernald had studied the African cichlid Astatotilapia burtoni, a freshwater fish about two inches long and dull pewter in color. By 2005 he had shown that among burtoni, the top male in any small population lives like some fishy pharaoh, getting far more food, territory, and sex than even the No. 2 male. This No. 1 male cichlid also sports a bigger and brighter body. And there is always only one No. 1.

I wonder, Fernald thought, what would happen if we just removed him?

So one day Fernald turned out the lights over one of his cichlid tanks, scooped out big flashy No. 1, and then, 12 hours later, flipped the lights back on. When the No. 2 cichlid saw that he was now No. 1, he responded quickly. He underwent massive surges in gene expression that immediately blinged up his pewter coloring with lurid red and blue streaks and, in a matter of hours, caused him to grow some 20 percent. It was as if Jason Schwartzman, coming to work one day to learn the big office stud had quit, morphed into Arnold Schwarzenegger by close of business."

[Likoma]

Thats an awesome read Simon.

A fair bit of time spent in the warm room while viewing the fish allows us to come up with theories of WHY. One of the things I have noticed is how you can change the demeanor and self image of a fish.

3 males and 7females in a tank. There is as constant battle between the 3 males. Remove the 2 top tier males and leave the 3rd tier male in the tanks for 3 months. His color and breeding fervor increase dramatically. Place all fish in a new aquarium and the then 3rd tier male is now the super duper dominant. I guess his time as alpha has bolstered his courage and self image to the point that he now takes on all comers.

So far we have replicated the effect in 3 different species. Its a great way to improve the coloring of individual fish.

Our new "social experiment" is rearing juvenile fish in an aquarium with adult fish. Hoping that it will work like a dog pack. Im hoping that they will learn there place in the social order of things.

[alanmin4304]

I don't think there is any change to the genetics. The males all have the ability to increase colour, they just don't do it while alpha male is around or they get beat up. It is just their turn to show who is boss when he is away.

[amtiskaw]

Genetics don't change, but active gene expression does :smln:

They don't have a look around, see they are now the dominant fish, and "decide" to start colouring up/putting on weight. Changes to environment turn on/off gene expression, and the changes happen automatically.

[Li@m]

:gopo:

[alanmin4304]

Would a change to the environment include previous alpha male being on holiday?

[calculator]

interesting aricle, thanks.

I did quite like the "t was as if Jason Schwartzman, coming to work one day to learn the big office stud had quit, morphed into Arnold Schwarzenegger by close of business." part.

[livingart]

Would a change to the environment include previous alpha male being on holiday?

yes