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Phylogenetic analysis of the human basic helix-loop-helix proteins.
Valérie Ledent1, Odier Paquet, Michel Vervoort
1Evolution et Développement des protostomiens, Centre de Génétique moléculaire, UPR 2167 CNRS, 1 Ave de la terrasse, 91198 Gif-sur-Yvette Cedex, France. vervoort@cgm.cnrs-gif.fr
Genome Biology
|July 3, 2002
Summary
The study identified 44 basic helix-loop-helix (bHLH) gene families, with 43 present in the last common ancestor of worms, flies, and humans. This highlights the genomic complexity of early animal evolution.
Area of Science:
- Evolutionary developmental biology
- Genomics
- Comparative genomics
Background:
- Basic helix-loop-helix (bHLH) proteins are crucial transcription factors in animal development.
- Identifying orthologous bHLH genes aids in reconstructing ancestral genomes.
Purpose of the Study:
- To identify and classify bHLH genes across different taxa.
- To infer the bHLH gene repertoire of the last common ancestor of animals.
Main Methods:
- Comparative analysis of bHLH gene families in Caenorhabditis elegans, Drosophila melanogaster, and Homo sapiens.
- Identification of orthologous relationships among bHLH genes.
Main Results:
- Identified 39 bHLH genes in worms, 58 in flies, and 125 in humans.
- Defined 44 orthologous bHLH families, with 43 present in the common ancestor of worms, flies, and humans.
- Found limited overlap of bHLH genes between animals and yeast or plants, suggesting independent diversification.
Conclusions:
- The last common ancestor of bilaterian animals possessed at least 43 distinct bHLH gene types.
- bHLH gene diversification is linked to the evolution of multicellularity.
- Significant bHLH gene diversification occurred independently in animal and plant lineages.