iSeq: A New Double-Barcode Method for Detecting Dynamic Genetic Interactions in Yeast

Area of Science:

• Systems biology
• Genetics
• Molecular biology

Background:

• Systematic genetic interaction screens are crucial for understanding biological networks.
• Current methods are limited to single environmental conditions, hindering a dynamic cellular view.
• High-throughput, replicable assays are needed to study genetic interactions across diverse environments.

Purpose of the Study:

• To introduce iSeq, a novel platform for building large double barcode libraries.
• To enable rapid assaying of genetic interactions across multiple environments.
• To assess the reproducibility and identify sources of variation in genetic interaction measurements.

Main Methods:

• Development of the iSeq platform for constructing double barcode libraries.
• Application of iSeq in yeast to measure fitness across three conditions for ~400 clonal strains.
• Whole-genome sequencing of 102 strains to identify genetic variations and mutations.

Main Results:

• iSeq demonstrates high reproducibility of fitness and interaction scores for identical clonal strains across replicates.
• Significant variability in genetic interaction scores was observed between replicates of the same putative genotype.
• Frequent occurrence of segregating variation and de novo mutations, including aneuploidy, was detected during strain construction.
• Several novel environment-dependent genetic interactions were identified.

Conclusions:

• The iSeq platform significantly enhances the throughput and replicability of genetic interaction assays.
• Understanding genetic variation within strains is critical for accurate interpretation of genetic interaction data.
• iSeq has the potential to greatly expand the knowledge of dynamic, environment-specific genetic interaction networks.