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07:54
Manipulation of Ploidy in Caenorhabditis elegans
Published on: March 15, 2018
Gene-balanced duplications, like tetraploidy, provide predictable drive to increase morphological complexity
Michael Freeling1, Brian C Thomas
1Department of Plant and Molecular Biology, University of California-Berkeley, Berkeley, California 94720, USA. freeling@nature.berkeley.edu
Genome Research
|July 5, 2006
Summary
The gene balance hypothesis explains rising morphological complexity in eukaryotes. Gene duplication and selection for dose-sensitive genes create functional modules, driving evolutionary increases in complexity.
Area of Science:
- Evolutionary biology
- Genomics
- Developmental biology
Background:
- The rising maximums of morphological complexity in eukaryotic evolution are debated.
- A "predictable drive" for increasing complexity has not been identified.
- The gene balance hypothesis, based on gene dosage effects, predicts gene content changes after duplication.
Purpose of the Study:
- To explain the trend of increasing maximum morphological complexity in eukaryotes.
- To test the gene balance hypothesis using genomic data.
- To propose "balanced gene drive" as a mechanism for evolutionary complexity.
Main Methods:
- Analysis of genomic data from chordate and angiosperm genomes.
- Examination of gene content changes following different types of gene duplication (e.g., tetraploidy).
- Application of gene balance theory to predict the fate of duplicate genes.
Main Results:
- Genomic data support the gene balance hypothesis's predictions.
- Tetraploidies and balanced segments bias gene pools towards dose-sensitive genes (e.g., transcription factors).
- Purifying selection maintains dose-sensitive duplicate genes as functional modules, precursors to coadapted gene complexes.
Conclusions:
- "Balanced gene drive" provides a sufficient explanation for increasing maximum morphological complexity in plants and animals.
- Eukaryotic evolution shows a consistent trend of increasing complexity over geological timescales.
- Functional modules arising from gene duplication and selection are key to this evolutionary drive.
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