Whole-genome duplication and molecular evolution in Cornus L. (Cornaceae) - Insights from transcriptome sequences

Area of Science:

• Evolutionary Biology
• Genomics
• Phylogenetics

Background:

• Whole-genome duplication (WGD) is a key driver of plant diversification.
• Molecular evidence for WGD in non-model plants remains underexplored.
• High-throughput transcriptome data offer new avenues for studying genome evolution.

Purpose of the Study:

• To investigate the molecular signals and evolutionary impact of WGD in the angiosperm genus Cornus.
• To reconstruct the phylogenetic history of genome duplication events within Cornus.
• To correlate WGD events with paleoclimatic changes and lineage diversification.

Main Methods:

• De novo transcriptome assembly for ten Cornus lineages and outgroups.
• Comparative phylogenetic analyses using molecular dating of orthologous genes.
• Analysis of synonymous substitution distributions between paralogous genes.
• Examination of molecular evolutionary rates through time.

Main Results:

• A shared WGD event was detected across all sampled Cornus taxa in the late Cretaceous.
• This WGD event temporally coincides with paleoclimatic shifts and the divergence of major Cornus lineages.
• Rates of molecular evolution accelerated post-WGD, with the highest rates in the herbaceous C. canadensis lineage.

Conclusions:

• Transcriptome data are valuable for studying genome evolution in closely related species.
• Late Cretaceous WGD likely played a significant role in the diversification of Cornus and flowering plants.
• Increased sea surface temperatures may have promoted WGD and subsequent plant evolution.