Polyploidy is widespread in Microsporidia

Area of Science:

• * Parasitology
• * Genomics
• * Evolutionary Biology

Background:

• * Microsporidia are obligate intracellular parasites with broad host ranges and significant economic/public health impacts.
• * Ploidy in Microsporidia is known to be variable, with few diploid and one known polyploid species.
• * Advances in genome sequencing enable comprehensive ploidy assessment across Microsporidia.

Purpose of the Study:

• * To estimate ploidy levels across the diversity of available Microsporidia genomic data.
• * To investigate the prevalence and dynamics of polyploidy within the Microsporidia phylum.
• * To analyze heterozygosity in polyploid Microsporidia and discuss implications for polyploidization events.

Main Methods:

• * Utilized k-mer-based analyses on Microsporidia genome data from the Sequence Read Archive.
• * Estimated ploidy levels for numerous Microsporidian datasets.
• * Calculated genome-wide heterozygosity for polyploid Microsporidian genomes.

Main Results:

• * Polyploidy is widespread across Microsporidia, indicating dynamic ploidy changes.
• * At least six Microsporidian species exhibit tetraploidy, with independent origins.
• * Polyploid Microsporidian genomes are surprisingly homozygous, despite their ploidy.

Conclusions:

• * Ploidy is a dynamic trait in Microsporidia, with widespread polyploidy.
• * Independent polyploidization events have occurred multiple times in Microsporidia.
• * The homozygous nature of polyploid genomes offers insights into their evolutionary history and origins.