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Evolution of size and pattern in the social amoebas.

Schaap P - Bioessays (2007)

Bottom Line: The foundation is a recently constructed molecular phylogeny of the Dictyostelia, which was used to examine trends in the evolution of novel forms and in the divergence of genes that shape these forms.The role of cAMP in aggregation arose through co-option of a pathway that originally acted to coordinate fruiting body formation.The genotypic changes that caused this innovation and the role of dynamic cAMP signaling in defining fruiting body size and pattern throughout social amoeba evolution are discussed.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, University of Dundee, MSI/WTB/JBC complex, Dow Street, Dundee DD1 5EH, UK. p.schaap@dundee.ac.uk

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The family tree of the social amoebas. The phylogenetic tree of the social amoebas, based on conserved SSU rDNA sequences from 1655 aligned positions, was constructed by Baldauf and coworkers,24 using Bayesian inference. The tree shows subdivision of nearly all known species of Dictyostelium (D.), Polysphondylium (P.), and Acytostelium (A.) into four major groups, which are indicated by separate colors. Separate analyses were conducted on group 4 sequences with an additional 300 nucleotide positions that were more divergent. The tree is rooted on SSU rDNA sequences of closely related solitary amoebas. (Previously published in Schaap R Winckler T, Nelson M, Alvarez-Curto E, Elgie B et al. 2006 Science 314:661–663 with permission of Science).
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fig03: The family tree of the social amoebas. The phylogenetic tree of the social amoebas, based on conserved SSU rDNA sequences from 1655 aligned positions, was constructed by Baldauf and coworkers,24 using Bayesian inference. The tree shows subdivision of nearly all known species of Dictyostelium (D.), Polysphondylium (P.), and Acytostelium (A.) into four major groups, which are indicated by separate colors. Separate analyses were conducted on group 4 sequences with an additional 300 nucleotide positions that were more divergent. The tree is rooted on SSU rDNA sequences of closely related solitary amoebas. (Previously published in Schaap R Winckler T, Nelson M, Alvarez-Curto E, Elgie B et al. 2006 Science 314:661–663 with permission of Science).

Mentions: Comparison of conserved DNA or protein sequences is a more direct and reliable method to establish genetic relationships. Two family trees of the social amoebas were constructed by comparing the DNA sequences of their small subunit ribosomal RNA (SSU rRNA) gene on one hand and the amino-acid sequences of their α-tubulin protein on the other. Both trees show that the similarities in fruiting body architecture only partially reflect an underlying genetic similarity.24 Instead, both the α-tubulin tree and the SSU rRNA tree shown here (Fig. 3) subdivide the 75 known species of social amoebas into four major groups. There are dictyostelids in all four groups. The acytostelids and all white polysphondylids are members of group 2, but the purple polysphondylid P. violaceum occupies a position between groups 3 and 4, and forms a small clade with the dictyostelid D. laterosorum. This indicates that at least two out of the three previously proposed genera are polyphyletic. Multiple origins for the polyspondylids were also predicted by a family tree that was based on 18 combined morphological traits.29


Evolution of size and pattern in the social amoebas.

Schaap P - Bioessays (2007)

The family tree of the social amoebas. The phylogenetic tree of the social amoebas, based on conserved SSU rDNA sequences from 1655 aligned positions, was constructed by Baldauf and coworkers,24 using Bayesian inference. The tree shows subdivision of nearly all known species of Dictyostelium (D.), Polysphondylium (P.), and Acytostelium (A.) into four major groups, which are indicated by separate colors. Separate analyses were conducted on group 4 sequences with an additional 300 nucleotide positions that were more divergent. The tree is rooted on SSU rDNA sequences of closely related solitary amoebas. (Previously published in Schaap R Winckler T, Nelson M, Alvarez-Curto E, Elgie B et al. 2006 Science 314:661–663 with permission of Science).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3045520&req=5

fig03: The family tree of the social amoebas. The phylogenetic tree of the social amoebas, based on conserved SSU rDNA sequences from 1655 aligned positions, was constructed by Baldauf and coworkers,24 using Bayesian inference. The tree shows subdivision of nearly all known species of Dictyostelium (D.), Polysphondylium (P.), and Acytostelium (A.) into four major groups, which are indicated by separate colors. Separate analyses were conducted on group 4 sequences with an additional 300 nucleotide positions that were more divergent. The tree is rooted on SSU rDNA sequences of closely related solitary amoebas. (Previously published in Schaap R Winckler T, Nelson M, Alvarez-Curto E, Elgie B et al. 2006 Science 314:661–663 with permission of Science).
Mentions: Comparison of conserved DNA or protein sequences is a more direct and reliable method to establish genetic relationships. Two family trees of the social amoebas were constructed by comparing the DNA sequences of their small subunit ribosomal RNA (SSU rRNA) gene on one hand and the amino-acid sequences of their α-tubulin protein on the other. Both trees show that the similarities in fruiting body architecture only partially reflect an underlying genetic similarity.24 Instead, both the α-tubulin tree and the SSU rRNA tree shown here (Fig. 3) subdivide the 75 known species of social amoebas into four major groups. There are dictyostelids in all four groups. The acytostelids and all white polysphondylids are members of group 2, but the purple polysphondylid P. violaceum occupies a position between groups 3 and 4, and forms a small clade with the dictyostelid D. laterosorum. This indicates that at least two out of the three previously proposed genera are polyphyletic. Multiple origins for the polyspondylids were also predicted by a family tree that was based on 18 combined morphological traits.29

Bottom Line: The foundation is a recently constructed molecular phylogeny of the Dictyostelia, which was used to examine trends in the evolution of novel forms and in the divergence of genes that shape these forms.The role of cAMP in aggregation arose through co-option of a pathway that originally acted to coordinate fruiting body formation.The genotypic changes that caused this innovation and the role of dynamic cAMP signaling in defining fruiting body size and pattern throughout social amoeba evolution are discussed.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, University of Dundee, MSI/WTB/JBC complex, Dow Street, Dundee DD1 5EH, UK. p.schaap@dundee.ac.uk

Show MeSH