Comparing levels of heterozygosity and loss-of-heterozygosity regions in probiotic yeasts

Abstract

This study is an analysis and comparison of heterozygosity levels and LOH regions of four probiotic yeast strains. LOH events are primarily caused by stressful conditions like DNA damage in the form of double-strand breaks. Four strains were mapped and sequenced onto the S288c S.cerevisiae reference genome to produce viable indels and SNPs. Galaxy, SAMtools, Picard tools, and GATK were utilised to determine and compare the levels of heterozygosity in the isolates. Visualisation of the results was done using allele plots that were accompanied by YMAP images. A steady decline in heterozygosity levels was observed amongst the strains, which indicates the presence of microevolution events such as mitotic recombination.