Partitioning transcript variation in Drosophila: abundance, isoforms, and alleles

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Multilevel transcription analysis requires advanced genomic tools.
• Previous methods had limitations in assessing differential expression, isoform usage, and allelic imbalance simultaneously.

Purpose of the Study:

• To introduce and validate a novel array design for comprehensive transcription analysis in Drosophila.
• To assess differential gene expression, alternative isoform usage, and allelic imbalance between sexes in Drosophila simulans.

Main Methods:

• Development of a high-density array (∼2.5 million features) with specialized modules for 3' expression, exon expression, and single nucleotide polymorphism (SNP) analysis.
• Application of the array to analyze gene expression and allelic variation in Drosophila simulans, comparing males and females.
• Validation of SNP probe sets using resequencing data.

Main Results:

• Identified significant differential gene expression between male and female Drosophila simulans (34% in 3' expression, 32% in exon modules).
• Detected alternative isoform usage in 164 genes between sexes.
• Achieved high concordance (>99%) between array-based SNP data and resequencing.
• Found allelic imbalance in 37% of examined probe sets with heterozygous SNP loci.

Conclusions:

• The new array design effectively facilitates multilevel transcription analysis in Drosophila.
• The tool is suitable for both Drosophila melanogaster and closely related species, enabling allele-specific expression and genotyping studies.