A phylogenetic analysis of macroevolutionary patterns in fermentative yeasts

Area of Science:

• Evolutionary Biology
• Microbial Ecology
• Phylogenetics

Background:

• Physiological innovations, like yeast fermentation, can drive adaptive radiations when new ecological opportunities arise.
• Adaptive radiation theory predicts a slowdown in diversification and morphological evolution after initial bursts.
• Yeasts (Saccharomycotina) present a model system due to their fermentation ability and potential for adaptive radiation.

Purpose of the Study:

• To test the "early burst" prediction for species diversification in yeasts.
• To investigate the evolutionary patterns of cell-size and fermentation versatility in yeasts.
• To explore the potential correlated evolution between cell-size and fermentation in yeast lineages.

Main Methods:

• Comparative phylogenetic analysis of yeast species.
• Analysis of species diversification rates over approximately 150 million years.
• Phylogenetic regression and disparity analysis to assess trait evolution (cell-size, fermentation versatility).

Main Results:

• Yeast speciation rates were found to be constant, not exhibiting an early burst pattern.
• Significant phylogenetic signal was detected for both cell-size and fermentation versatility.
• Cell-size evolution showed accelerated diversification, and a significant correlation was found between cell-size and fermentation versatility.

Conclusions:

• The "early burst" model of adaptive radiation is not supported for yeast species diversification or the studied traits.
• Correlated evolution exists between yeast cell-size and fermentation versatility.
• Whole genome duplication in yeasts did not show a statistically detectable phenotypic effect at this analytical level, warranting further investigation.