Wired for change: Gene expression study reveals first steps of evolution in gene regulation

Aug 02, 2013
Wired for change
Studying very closely related strains provides a more precise view of how gene regulation evolves.

A study of gene expression led by scientists at the EMBL-European Bioinformatics Institute (EMBL-EBI) and the University of Cambridge has revealed the first steps of evolution in gene regulation in mice. Published in the journal Cell, the research has implications for the study of differences in gene regulation between people.

"We found an impressive amount of variation between these apparently very similar in terms of transcription-factor binding, which is an important indicator of gene-regulation activity," says Paul Flicek of EMBL-EBI. "Often you'll see a specific combination of these acting in concert – and it was fascinating for us to see just how important these combinations are. They're much more likely to be conserved over the course of evolution than whatever DNA sequence they might be binding to."

The team studied in five very closely related mouse species in order to pinpoint changes at the very earliest stages of evolution. To do this, they compared the way that three transcription factors (TFs) bind to genes to control if they're turned on or off in in the different mouse species.

"By looking at mice that are very closely related to each other, we were able to capture a snapshot of what regulatory evolution is happening," explains Duncan Odom of the University of Cambridge. "That's important because it's much harder to see how something has evolved when you don't have a clear picture of the starting point."

Say you wanted to know how an orange tree evolved, but you could only compare it to an elm or oak. You'd have greater insight into how an orange tree evolved if you could compare it to much more closely related plants like grapefruit and lemons, which could give insight into how each came from an ancestral citrus plant. In this study, instead of comparing leaf and fruit shapes, the team looked at gene regulation in mice that had only recently diverged from one another. They demonstrated that TFs work in clusters that are conserved in order to ensure genetic and evolutionary stability.

The researchers contrasted their findings with gene-regulation data from another model organism, Drosophila, to see where the similarities lay. They found that there were a lot more differences between closely related mouse strains than there are between distantly related fruit-fly strains.

"Mammals have lots of DNA kicking around that doesn't code for proteins, while fruit flies have relatively little. So a mouse's regulatory wiring will just have a lot more wiggle room than a fruit fly's," says Paul. "That gives us a clearer picture of what we can expect to learn about mammalian genetic regulation from fruit flies."

The study could help scientists understand how differs from one person to the next, explaining why genes that cause disease in some people don't have that effect in others.

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More information: Stefflova, K., et al. (2013) Cooperativity and rapid evolution of co-bound transcription factors in closely related mammals. Cell, published online 1 August 2013. DOI: 10.1016/j.cell.2013.07.007

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JVK
1 / 5 (2) Aug 02, 2013

Kohl, J.V. (2012) Human pheromones and food odors: epigenetic influences on the socioaffective nature of evolved behaviors. Socioaffective Neuroscience & Psychology, 2: 17338.

The molecular mechanisms that link food odors to genes, hormones, and behavior are the same in species from microbes to man, and they also link pheromones to genes, hormones, and human behavior.

See also: Kohl, J.V. (2013) Nutrient-dependent/pheromone-controlled adaptive evolution: a model. Socioaffective Neuroscience & Psychology, 3: 20553.

evolution3
not rated yet Aug 03, 2013

Kohl, J.V. (2012) Human pheromones and food odors: epigenetic influences on the socioaffective nature of evolved behaviors. Socioaffective Neuroscience & Psychology, 2: 17338.

The molecular mechanisms that link food odors to genes, hormones, and behavior are the same in species from microbes to man, and they also link pheromones to genes, hormones, and human behavior.

See also: Kohl, J.V. (2013) Nutrient-dependent/pheromone-controlled adaptive evolution: a model. Socioaffective Neuroscience & Psychology, 3: 20553.


So?
JVK
1 / 5 (2) Aug 03, 2013
Gene expression is nutrient-dependent and pheromone-controlled. I apologize for not establishing the context (adaptive evolution) which I thought had already been established in "Gene expression study reveals first steps of evolution in gene regulation. The first step involves sensory input from the environment that activates gene expression. DNA does nothing by itself; it's like a blueprint for a building (per Bruce Lipton) and blueprints do not automagically assemble buildings (except perhaps in theory).