Extensive non-redundancy in a recently duplicated developmental gene family

Area of Science:

• Evolutionary biology
• Genetics
• Developmental biology

Background:

• Recent gene duplication is hypothesized to lead to functional redundancy.
• Paralogous genes are assumed to be more similar in sequence if recently duplicated.
• The nematode-specific Warthog gene family, related to Hedgehog signaling, was studied.

Purpose of the Study:

• To test the hypothesis that recently duplicated genes are more functionally redundant.
• To investigate the evolutionary origin and function of the Warthog gene family in Caenorhabditis elegans.
• To examine functional redundancy among paralogues within the Warthog family.

Main Methods:

• Molecular phylogenetics to determine evolutionary origins.
• Genetic analysis in the model organism Caenorhabditis elegans.
• Construction and analysis of double and triple gene mutants.

Main Results:

• Warthog genes have acquired new roles in post-embryonic development, including left-right asymmetry and cell fate determination.
• Recently derived Warthog paralogues did not exhibit functional redundancy.
• A pair of evolutionarily divergent Warthog genes showed functional redundancy in cuticle biosynthesis.

Conclusions:

• Newer members of taxon-restricted gene families are not always functionally redundant.
• Older paralogues can exhibit functional redundancy, contradicting current gene evolution frameworks.
• Functional redundancy is not solely determined by the recency of gene duplication.