Monday, 28 January 2013

On genes controlling behaviour, or the burrow habits of mice

A recent article in Nature magazine discussed the burrow habits of mice. Scientists are studying these wild burrows, cross-breeding different species of mice.

They've unearthed some interesting stuff on links between behaviour and DNA, for example in studying why some species of mice dig fancy escape tunnels in their burrows whilst others stick with the humble hole-in-the-ground.
By studying the DNA of both wild oldfield mice(doesn't the name oldfield make you think of a mouse with a sergeant's cap and moustache waving around a rapier?) and deer mice, scientists have now been able to find out that burrowing behaviour is in the genes, not learned.
Deer mice
Oldfield Mice

So basically oldfield mice burrow these incredibly complex tunnels with escape routes when they dig holes in the ground. Researches have now found out that this behaviour is written in their genes, and not learned from watching parents/peers/acquaintances do the same. This burrowing behaviour, which wild deer mice do not exhibit, is interesting. Deer mice, on the other hand, dig simple holes in the ground which contrast 

with the vastly complicated structures oldfield mice build. Poor deer mice. (There's a diagram showing both forms of burrow at the end of this post).
This study gives an example of how closely genes can control and influence complicated behaviour are, as well as how complex the genes that determine such behaviour have to be.
The scientists who looked into this behaviour started out by studying burrow patterns of oldfield mice. They looked at the burrows created in a big box they filled with sand and saw the burrows were all very consistent; this suggests the burrows are genetically influenced. They then crossed deer mice with oldfield mice(yes, they can interbreed), and studied the burrow habits of the F1 generation. They then back-crossed this generation with original deer mice and again studied their burrowing habits.
The study follows Richard Dawkin's theory of the 'extended phenotype' (you may have read his book on the subject). Basically this is the effect a gene has on the environment of its particular organism. Mouse burrows is a perfect example of this; a gene affecting the environment. It will be interesting in the future to study other organisms(maybe beavers, or even dogs) to see how their behaviour and the environment around them is influenced by genes.
From Nature magazine. showing the burrow habits of the two species.

The BBC, the New York Times and Nat. Geographic have also reported on the research, if you want to read more about it/don't have a Nature magazine subscription.

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