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Myosin superfamily evolutionary history
Reid F Thompson1, George M Langford
1Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
The Anatomical Record
|October 17, 2002
Summary
The myosin superfamily evolved early myosin groups (I and II), with later specialized classes emerging across diverse organisms. This evolutionary analysis reveals myosin gene distribution and loss patterns in eukaryotes.
Area of Science:
- Molecular Biology
- Evolutionary Biology
- Cell Biology
Background:
- The myosin superfamily comprises at least 18 classes in eukaryotic cells.
- Classification is based on phylogenetic analysis of head domains, offering functional insights but not evolutionary history.
Purpose of the Study:
- To establish the evolutionary history of the myosin superfamily.
- To analyze the representation of myosin gene families across a broad taxonomic spectrum.
Main Methods:
- Phylogenetic analysis of 232 myosin heavy chain amino acid sequences.
- Inclusion of 65 organisms from protist, plant, and animal kingdoms.
- Construction of an organismal phylogenetic tree using complementary taxonomic schemes.
Main Results:
- Myosins II and I are hypothesized as the earliest evolving myosin groups.
- Myosins V (animal) and XI (plant) diverged from a common myosin II-like ancestor.
- Specific myosin classes emerged at different evolutionary stages, with some having limited organismal distribution.
Conclusions:
- Early myosin families likely function as generalists, while later families evolved as specialists with restricted roles.
- Evolutionary data can predict the presence or absence of myosin genes in species.
- The study provides a framework for understanding myosin evolution and gene distribution.
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