Intertidal population genetic dynamics at a microgeographic seascape scale

Area of Science:

• Marine Biology
• Genetics
• Ecology

Background:

• Intertidal zones are harsh environments shaping marine organism genetics.
• Most studies focus on large-scale factors, neglecting microgeographic influences on sessile species.
• Little is known about genetic differentiation in seaweeds due to tidal gradients.

Purpose of the Study:

• Investigate microgeographic genetic differentiation in the red seaweed Chondrus crispus.
• Assess the impact of tidal height on genetic connectivity and ploidy levels.
• Understand the role of reproductive traits in intertidal genetic dynamics.

Main Methods:

• Elaborate sampling strategy along a 90-m transect.
• Genome-scale analysis of genetic differentiation.
• Detection of ploidy level biases and Hardy-Weinberg equilibrium deviations.

Main Results:

• Significant genetic differentiation observed between high- and low-shore stands.
• Restricted genetic exchange within high-shore habitats.
• Intergametophytic nonrandom fertilization causes deviations from Hardy-Weinberg equilibrium.

Conclusions:

• Tidal height is a significant driver of microgeographic genetic structure in intertidal seaweeds.
• Reproductive strategies play a key role in shaping genetic diversity and evolutionary trajectories.
• These findings are crucial for understanding speciation and diversification in marine organisms.