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The evolution of dopamine systems in chordates
Kei Yamamoto1, Philippe Vernier
1Neurobiology and Development (UPR3294), Institute of Neurobiology Alfred Fessard, CNRS Gif-sur-Yvette, France.
Frontiers in Neuroanatomy
|April 13, 2011
Summary
Dopamine (DA) systems evolved early in chordates, with shared components suggesting a common origin with other monoamines. Gene duplication and functional flexibility drove DA system diversification across vertebrates.
Area of Science:
- Neuroscience
- Evolutionary Biology
- Molecular Biology
Background:
- Dopamine (DA) neurotransmission is fundamental to the central nervous system (CNS) across chordates.
- Shared molecular components suggest a common evolutionary origin for DA and other monoamine systems.
Purpose of the Study:
- To investigate the evolutionary history and diversification of DA systems in the CNS.
- To explore the role of gene duplication and functional flexibility in DA system evolution.
Main Methods:
- Comparative analysis of DA system components across chordate lineages.
- Examination of gene evolution, focusing on tyrosine hydroxylase (TH) genes.
- Review of anatomical and functional data on DA systems in various vertebrate groups.
Main Results:
- DA systems predate chordate divergence, with early diencephalic DA cells.
- A second tyrosine hydroxylase gene (TH2) suggests ancestral DA-synthesizing cells lost in placental mammals.
- Midbrain DA cells likely emerged within the vertebrate lineage, linked to midbrain-hindbrain development.
Conclusions:
- The evolution of DA systems involved early origins, gene duplication, and subsequent diversification.
- These evolutionary processes facilitated adaptation of brain functions to diverse vertebrate lifestyles.
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