The First Microsatellite-based Characterisation of Blastocystis sp. ST3 Isolates and Population Structure Analysis

Area of Science:

• Microbiology
• Genetics
• Parasitology

Background:

• Blastocystis sp. is a common intestinal Stramenopile found in humans and animals.
• Genetic diversity within Blastocystis has been explored using various molecular techniques, identifying numerous subtypes (ST).
• Blastocystis sp. subtype 3 (ST3) is the most prevalent subtype in human fecal samples.

Purpose of the Study:

• To characterize microsatellite loci in Blastocystis sp. ST3.
• To analyze the population structure of Blastocystis sp. ST3.
• To investigate the genetic variability of the most common human-infecting Blastocystis subtype.

Main Methods:

• Whole-genome analysis of Blastocystis sp. ST3 was performed to identify microsatellites with at least eight repeat units.
• Specific primers were designed, and bioinformatics tools were used to identify polymorphisms.
• Microsatellite typing was conducted on 18 Blastocystis sp. ST3 genomic DNA samples.

Main Results:

• A whole-genome scan identified 12 microsatellite loci with at least eight repeats in Blastocystis sp. ST3.
• Eight selected microsatellite loci were successfully amplified and used for genotyping.
• Microsatellite polymorphism analysis revealed a unique genetic profile for each of the 18 isolates, indicating high variability. The isolates were also categorized into two distinct population clusters.

Conclusions:

• Blastocystis sp. ST3 isolates demonstrate substantial variability in microsatellite repeats.
• Polymorphic microsatellite loci provide a novel and effective method for detailed investigation of genetic diversity and population structure in Blastocystis sp. ST3.