Oolon Colluphid
31 Mar 2009, 10:50 AM
BMC Evolutionary Biology 2009, 9:28 (3 February 2009)
Emergence, development and diversification of the TGF-β signalling pathway within the animal kingdom (http://www.biomedcentral.com/1471-2148/9/28)
Huminiecki et al.
Background
The question of how genomic processes, such as gene duplication, give rise to co-ordinated organismal properties, such as emergence of new body plans, organs and lifestyles, is of importance in developmental and evolutionary biology. Herein, we focus on the diversification of the transforming growth factor-β (TGF-β) pathway – one of the fundamental and versatile metazoan signal transduction engines.
Results
After an investigation of 33 genomes, we show that the emergence of the TGF-β pathway coincided with appearance of the first known animal species. The primordial pathway repertoire consisted of four Smads (http://en.wikipedia.org/wiki/SMAD_(protein)) (proteins that regulate TGF-β activity) and four receptors, similar to those observed in the extant genome of the early diverging tablet animal (Trichoplax adhaerens).
We subsequently retrace duplications in ancestral genomes on the lineage leading to humans, as well as lineage-specific duplications, such as those which gave rise to novel Smads and receptors in teleost fishes.
We conclude that the diversification of the TGF-β pathway can be parsimoniously explained according to the 2R model, with additional rounds of duplications in teleost fishes. Finally, we investigate duplications followed by accelerated evolution which gave rise to an atypical TGF-β pathway in free-living bacterial feeding nematodes of the genus Rhabditis.
Conclusion
Our results challenge the view of well-conserved developmental pathways. The TGF-β signal transduction engine has expanded through gene duplication, continually adopting new functions, as animals grew in anatomical complexity, colonized new environments, and developed an active immune system.
The TGF beta is the thing that controls cell proliferation and differentiation -- so this is stuff from deep, deep in our (and all animals') evolutionary history.
The 2R hypothesis suggests that "the genomes of the early vertebrate lineage underwent one or more complete genome duplications, and thus modern vertebrate genomes reflect paleopolyploidy."
Thread on this. (http://secularcafe.org/showthread.php?t=991)
Tags: cell signalling pathway genome
Emergence, development and diversification of the TGF-β signalling pathway within the animal kingdom (http://www.biomedcentral.com/1471-2148/9/28)
Huminiecki et al.
Background
The question of how genomic processes, such as gene duplication, give rise to co-ordinated organismal properties, such as emergence of new body plans, organs and lifestyles, is of importance in developmental and evolutionary biology. Herein, we focus on the diversification of the transforming growth factor-β (TGF-β) pathway – one of the fundamental and versatile metazoan signal transduction engines.
Results
After an investigation of 33 genomes, we show that the emergence of the TGF-β pathway coincided with appearance of the first known animal species. The primordial pathway repertoire consisted of four Smads (http://en.wikipedia.org/wiki/SMAD_(protein)) (proteins that regulate TGF-β activity) and four receptors, similar to those observed in the extant genome of the early diverging tablet animal (Trichoplax adhaerens).
We subsequently retrace duplications in ancestral genomes on the lineage leading to humans, as well as lineage-specific duplications, such as those which gave rise to novel Smads and receptors in teleost fishes.
We conclude that the diversification of the TGF-β pathway can be parsimoniously explained according to the 2R model, with additional rounds of duplications in teleost fishes. Finally, we investigate duplications followed by accelerated evolution which gave rise to an atypical TGF-β pathway in free-living bacterial feeding nematodes of the genus Rhabditis.
Conclusion
Our results challenge the view of well-conserved developmental pathways. The TGF-β signal transduction engine has expanded through gene duplication, continually adopting new functions, as animals grew in anatomical complexity, colonized new environments, and developed an active immune system.
The TGF beta is the thing that controls cell proliferation and differentiation -- so this is stuff from deep, deep in our (and all animals') evolutionary history.
The 2R hypothesis suggests that "the genomes of the early vertebrate lineage underwent one or more complete genome duplications, and thus modern vertebrate genomes reflect paleopolyploidy."
Thread on this. (http://secularcafe.org/showthread.php?t=991)
Tags: cell signalling pathway genome