Physiological characterization of the emergence from diapause: A transcriptomics approach

Area of Science:

• Marine biology
• Molecular biology
• Arctic ecology

Background:

• High-latitude organisms, including marine copepods, exhibit adaptations like diapause for survival.
• The physiological mechanisms governing the timing of complex life histories, especially in deep-sea diapausing copepods, remain unclear.

Purpose of the Study:

• To investigate the molecular events and gene expression patterns during the transition from diapause to egg release in the sub-Arctic copepod Neocalanus flemingeri.

Main Methods:

• Specimens of Neocalanus flemingeri were collected from deep waters in the sub-Arctic Pacific.
• Females were incubated under controlled conditions (dark, 4-5°C) and sampled weekly for RNA-Seq analysis.

Main Results:

• Diapause phenotype is characterized by reduced protein turnover and increased expression of stress-related genes.
• Reproductive activation involves upregulation of genes for germline development and oogenesis.
• Spermatogenesis activation at 5 weeks suggests maturation of stored sperm.

Conclusions:

• Gene expression profiles provide a molecular framework for staging field-collected females.
• The 7-week transition suggests reproductive program initiation in November for January spawners.