Muller's Ratchet and Ribosome Degeneration in the Obligate Intracellular Parasites .

are fungi-like parasites that have the smallest known eukaryotic genome, and for that reason they are used as a model to study the phenomenon of genome decay in parasitic forms of life. Similar to other intracellular parasites that reproduce asexually in an environment with alleviated natural selection, experience continuous genome decay that is driven by Muller's ratchet-an evolutionary process of irreversible accumulation of deleterious mutations that lead to gene loss and the miniaturization of cellular components. Particularly, have remarkably small ribosomes in which the rRNA is reduced to the minimal enzymatic core.

Error-prone protein synthesis in parasites with the smallest eukaryotic genome.

Microsporidia are parasitic fungi-like organisms that invade the interior of living cells and cause chronic disorders in a broad range of animals, including humans. These pathogens have the tiniest known genomes among eukaryotic species, for which they serve as a model for exploring the phenomenon of genome reduction in obligate intracellular parasites. Here we report a case study to show an apparent effect of overall genome reduction on the primary structure and activity of aminoacyl-tRNA synthetases, indispensable cellular proteins required for protein synthesis.