Candida albicans isolates contain frequent heterozygous structural variants and transposable elements within genes...

Area of Science:

• Genomics
• Mycology
• Evolutionary Biology

Background:

• * Candida albicans is a major human fungal pathogen responsible for significant mortality and antifungal resistance.
• * As a heterozygous diploid with asexual reproduction, C. albicans relies on genomic rearrangements like structural variants (SVs) for variation.
• * Transposable elements (TEs) are mobile genetic sequences that can contribute to genomic instability and evolution.

Purpose of the Study:

• * To comprehensively investigate the landscape of SVs and TEs in diverse clinical isolates of C. albicans.
• * To understand the impact of SVs and TEs on gene expression and intraspecies genetic diversity.
• * To explore the role of SVs in centromere evolution within C. albicans.

Main Methods:

• * Performed long-read sequencing on three distantly related clinical isolates of C. albicans.
• * Conducted genome-wide SV analysis and detailed characterization of TE composition, location, and diversity.
• * Screened an additional 100 clinical isolates for specific centromeric SVs.

Main Results:

• * Identified frequent co-occurrence of SVs and TEs near coding sequences, often in heterozygous states, suggesting potential regulatory roles.
• * Demonstrated that most SVs are isolate-specific, highlighting their contribution to intraspecies genetic variation.
• * Discovered widespread, often heterozygous, SVs at the centromeres of Chromosomes 4 and 5 in clinical isolates, indicating active centromere evolution.

Conclusions:

• * SVs and TEs are prevalent across diverse clinical C. albicans isolates, contributing significantly to its genetic variability.
• * Centromeres of C. albicans are hotspots for genome rearrangement, with SVs playing a key role in their evolution.
• * These findings underscore the importance of SVs and TEs in the adaptation and evolution of this opportunistic fungal pathogen.