Origin and evolution of yeast carotenoid pathways.

Area of Science:

• Biochemistry
• Evolutionary Biology
• Genetics

Background:

• Carotenoid biosynthesis pathways are present across all domains of life.
• Understanding the evolutionary history of these pathways provides insights into early cellular life and gene transfer events.

Purpose of the Study:

• To elucidate the origin and evolution of carotenoid biosynthesis genes.
• To trace the inheritance and independent emergence of carotenoid pathways in different life forms.

Main Methods:

• Comparative analysis of genes involved in carotenoid biosynthesis.
• Phylogenetic distribution of carotenogenic genes across prokaryotes and eukaryotes.

Main Results:

• Carotenoid biosynthesis originated from an early common ancestor of prokaryotes.
• Genes were inherited by Bacteria and Archaea, with fungi inheriting them from Archaea.
• Algal-plant carotenoid pathways evolved independently through endosymbiotic gene transfer from cyanobacteria.
• The ancestral gene set included crtB, crtI, and crtYcd for beta-carotene synthesis.
• Diversification in bacteria and fungi resulted from gene modification and novel gene acquisition.

Conclusions:

• Carotenoid biosynthesis pathways have a deep evolutionary history, originating in early prokaryotes.
• Horizontal gene transfer and endosymbiosis played significant roles in the distribution and evolution of these pathways.
• Specific gene sets and modifications led to the diverse carotenoid profiles observed in various organisms, including red yeasts.