Diapause vs. reproductive programs: transcriptional phenotypes in a keystone copepod

Area of Science:

• Marine Biology
• Molecular Ecology
• Developmental Biology

Background:

• Arthropods use diapause, a seasonal dormancy, to synchronize reproduction with environmental conditions.
• The copepod Calanus finmarchicus in the North Atlantic exhibits variable life cycles, including diapause, but triggers remain unclear.

Purpose of the Study:

• To identify molecular markers and biological processes differentiating diapause from reproductive development in Calanus finmarchicus.
• To establish protocols for distinguishing between these developmental programs using transcriptomic data.

Main Methods:

• Analysis of transcriptomic data from copepods using dimensionality reduction of gene expression.
• Functional analyses to identify program-specific genes and biological processes.
• Differential gene expression analysis to confirm identified gene sets.

Main Results:

• Distinct gene expression patterns were observed between individuals on reproductive and diapause programs.
• Gene expression in the diapause program showed minimal change over time, unlike the reproductive program.
• Genes related to RNA metabolism and 54 differentially expressed genes (up-regulated in diapause) were identified as key indicators.

Conclusions:

• Transcriptomic analysis successfully differentiated between diapause and reproductive developmental programs in Calanus finmarchicus.
• Genes involved in RNA metabolism, oogenesis, and fatty acid biosynthesis are crucial indicators of diapause preparation.
• These identified genes provide valuable targets for future functional studies on diapause mechanisms.