Current hypotheses to explain genetic chaos under the sea

Area of Science:

• Marine Biology
• Population Genetics
• Evolutionary Biology

Background:

• Chaotic genetic patchiness (CGP) describes unexpected spatial and temporal genetic structure in marine species.
• This phenomenon occurs at scales where larval dispersal should homogenize genetic variation.
• Understanding CGP is crucial for marine conservation and fisheries management.

Purpose of the Study:

• To review and discuss four primary mechanisms that generate chaotic genetic patchiness.
• To synthesize current knowledge on selection, sweepstakes reproductive success, collective dispersal, and temporal population dynamics as drivers of CGP.
• To provide a comprehensive overview of the processes underlying genetic structuring in marine populations.

Main Methods:

• Literature review and synthesis of existing studies on CGP.
• Discussion of theoretical models for sweepstakes reproductive success and collective dispersal.
• Analysis of empirical examples illustrating the proposed mechanisms.

Main Results:

• Diversifying selection can drive genetic differentiation at specific loci.
• Neutral demographic processes, such as sweepstakes reproductive success, accelerate genetic drift and create genome-wide effects.
• Collective dispersal can maintain genetic structure by preventing complete mixing of larval cohorts.
• Temporal shifts in local population dynamics also contribute to CGP.

Conclusions:

• Multiple mechanisms, including selection and neutral processes, can explain CGP in marine species.
• The interplay of these factors, rather than a single cause, likely drives observed genetic patterns.
• Further research into temporal dynamics and the combined effects of different mechanisms is warranted.