Comparative genomic of Blastocystis. Comparison between draft genomes of Blastocystis isolates from human samples in Bogotá, Colombia

Blastocystis is the most common eukaryotic microorganism colonizing the intestines of both humans and animals. The vast genetic variability and difficulties in establishing and maintaining axenic cultures complicate large-scale genomic investigations aimed at understanding their biological characteristics. In Colombia, the genomic characteristics of circulating subtypes (ST) are not known. To address this problem, we established 9 xenic Blastocystis cultures from human fecal samples. DNA was extracted and sequenced from these cultures using Illumina and Oxford Nanopore technologies. The genomic DNAs obtained corresponded to ST1 (n=3), ST2 (n=1), ST3 (n=2), ST7 (n=1), and ST8 (n=2). We found remarkable diversity in terms of the size of the genomes and the percentage of GC. The draft genomes obtained with Illumina contained between 852 to 1037 scaffolds, spanning 12 – 24 Mb, with N50 between 10000-28000 bp, while the ST1 genome sequenced with Oxford Nanopore technology consisted of 20 Mb in 116 scaffolds, with N50 of 168718 bp. This is the first Blastocystis genome sequencing study in Colombia and South America. These results constitute the initial steps for learning and understanding the genomic structure of this controversial microorganism in order to increase the information available for future studies.