Pollutant-induced changes in fish pigmentation and spatial patterns

Area of Science:

• Developmental biology
• Environmental toxicology
• Mathematical modeling

Background:

• Pigmentation abnormalities in fish can indicate developmental disruption from environmental contaminants.
• The precise mechanisms linking contaminant exposure to altered fish pigmentation patterns are not well understood.
• Pigment cell interactions are crucial for pattern formation during fish development.

Purpose of the Study:

• To investigate how environmental pollutants influence pigment cell self-organization and pattern formation in fish.
• To model the effects of altered cell-cell interactions on pigmentation using a reaction-diffusion-advection framework.

Main Methods:

• A continuum reaction-diffusion-advection model was developed to simulate pigment cell behavior.
• Non-local Morse-type kernels were incorporated to represent short- and long-range interactions between melanophores and xanthophores.
• Simulations explored the impact of perturbing adhesion and repulsion strengths on pattern formation.

Main Results:

• Altered cell adhesion or repulsion strengths can induce transitions between striped, spotted, and mixed pigmentation patterns.
• Homotypic interactions, particularly among melanophores, are sensitive to contamination, affecting cell density and overall pattern.
• Short-term contaminant exposure may lead to recoverable pigment changes, while prolonged exposure can cause sustained pigment loss.
• Contaminant-induced changes in cell-cell interactions directly impact stripe formation rate, stripe number, and pigmentation levels in developing fish.

Conclusions:

• This study provides a mechanistic link between environmental contaminant exposure and observed pigmentation alterations in fish.
• The findings highlight the sensitivity of pigment cell interactions to pollutants and their role in determining adult fish pigmentation patterns.
• The model offers insights into how environmental factors can disrupt developmental processes, leading to specific phenotypic changes.