Combining next-generation sequencing and microarray technology into a transcriptomics approach for the non-model...

Area of Science:

• Genomics and Bioinformatics
• Environmental Toxicology
• Molecular Biology

Background:

• Whole-transcriptome gene-expression analysis typically requires sequenced genomes and available microarrays.
• Non-model organisms, lacking these resources, present challenges for transcriptomic studies.
• Developing annotated transcriptomes and validated gene-expression microarrays is essential for these species.

Purpose of the Study:

• To establish an advanced approach for creating transcriptomics resources for non-model organisms.
• To combine next-generation sequencing (NGS) and microarray technology for resource development.
• To apply this approach to Chironomus riparius for enhanced ecotoxicity testing.

Main Methods:

• Generated 1.5 million NGS reads from Chironomus riparius across developmental stages and toxicant exposure.
• Designed probes (844k on NGS reads, 76k on related species ESTs) and tested their affinity using a 1M probe-selection microarray.
• Assembled NGS data into isotigs and singletons, annotated them with Gene Ontology terms, and developed an algorithm integrating assembly and probe affinities to select 59k reliable probes.

Main Results:

• Developed 59,000 highly reliable probes targeting 95% of isotigs and 18% of singletons.
• Created an annotated transcriptome and a validated gene-expression microarray for Chironomus riparius.
• The developed resources enable whole-transcriptome gene-expression analysis in this non-model organism.

Conclusions:

• The combined NGS and microarray approach successfully developed high-quality transcriptomics resources for Chironomus riparius.
• This methodology is applicable to other non-model organisms lacking genomic data.
• The resources are expected to significantly advance ecotoxicity testing using Chironomus riparius.