Ancient origins of human developmental plasticity

Area of Science:

• Comparative physiology
• Neuroendocrinology
• Evolutionary biology

Background:

• Animals exhibit adaptive plasticity in development, physiology, growth, and behavior in response to environmental cues.
• Life history transitions like metamorphosis and birth are timed by balancing growth opportunities against mortality risks.
• The neuroendocrine stress axis integrates environmental and internal signals to modulate these adaptive responses.

Purpose of the Study:

• To investigate the role of the neuroendocrine stress axis in mediating adaptive responses to environmental conditions.
• To explore the involvement of corticotropin-releasing factor (CRF) in regulating developmental hormone secretion and life history timing.
• To examine the long-term phenotypic consequences of early-life stress hormone exposure.

Main Methods:

• Review of existing evidence on animal responses to environmental factors.
• Analysis of the neuroendocrine pathways controlling developmental hormones (corticosteroids and thyroid hormones).
• Examination of studies on CRF's role in metamorphosis and birth timing in various species.

Main Results:

• The neuroendocrine stress axis, particularly involving CRF, is a conserved mechanism controlling developmental hormones.
• CRF stimulates thyroid and corticosteroid hormone secretion, influencing accelerated metamorphosis in tadpoles and birth timing in mammals.
• Early-life exposure to stress hormones can lead to lasting phenotypic changes.

Conclusions:

• The integrated neuroendocrine stress response is crucial for timing critical life history events.
• This stress response pathway plays a significant role in establishing long-term phenotypic characteristics.
• The evolutionary origins of this adaptive stress response trace back to early vertebrates.