by Patrick T. McGrath
Current Opinion in Neurobiology 2012, 23: 1-5
- Behavioral variation in different time scales:
1) learning or experience driven changes
2) evolutionary change
- The genetic basis of heritable behavioral differences is complex with multiple genetic variants of small effects.
- How genetic differences between individuals cause behavioral difference?
- Many trait differences are caused by a complex combination of genetic changes distributed throughout the genome.
- Coding changes, duplications, small noncoding RNA changes, cis -regulatory changes, neural specific alternative splicing changes
- How do the underlying genetic networks impact the types of genetic variants?
Comparison and contrast between evolution of behavior and development
- Development of body - largely controlled by gene
- Development of Behavior - genetic, acquired information, environment, internal state
Evolution of sensory systems
Three drivers for sensory evolution
1) Change of environment - heterogenetic, changing both spatially and temporally
2) Animals only sense a subset of their environment or stimuli that are also changing
3) Animals obtain information through proxies that can be sensed
1) Evolution of sensory genes reproducible upon an environmental shift
- Strains of C. elegans grown at high density for long periods of time have become resistant to dauer-inducing pheromones
- This is caused by deletions of pheromon receptor genes
2) Evolution of a metabotropic bioamine receptor
- Changes in connection between behavior state and sensory systems
- Changes nearby tyra-3 gene (G-protein-coupled receptor for norephinephrine)
- Increased expression of tyra-3 in a pair of sensory neurons correlated with and sufficient to cause a decreased frequency of leaving a depleting food source.
- The genetic change seems to modify how an internal state of the animal affects behavior.
- Changes are not only in genes themselves but changes in regulation of these genes at cis-regulatory regions.
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