Transcriptome-Derived Microsatellites Demonstrate Strong Genetic Differentiation in Pacific White Sharks

Area of Science:

• Population genetics
• Conservation genetics
• Marine biology

Background:

• Genome-scale sequencing advances enable high-resolution genetic markers for nonmodel organisms.
• Transcriptome sequencing is valuable for generating functional genomic markers for population studies.
• Understanding white shark (Carcharodon carcharias) population structure is crucial for conservation of this vulnerable species.

Purpose of the Study:

• To develop and utilize transcriptome-derived microsatellite markers for white shark population genetic analysis.
• To assess the cross-Pacific connectivity of white shark populations.
• To compare the efficacy of transcriptome-derived versus anonymous genomic markers in detecting population differentiation.

Main Methods:

• Development of 30 microsatellite markers from white shark heart transcriptome data.
• Genotyping of Southwestern Pacific (n=19) and Northeastern Pacific (n=20) white sharks using transcriptome and published anonymous markers.
• Analysis of genetic differentiation (FST, G″ST) between populations.

Main Results:

• Significant genetic differentiation (FST = 0.083, P = 0.05; G″ST = 0.200, P = 0.001) was detected between Southwestern and Northeastern Pacific white shark populations, indicating restricted gene flow.
• Transcriptome-derived microsatellite markers revealed up to twofold higher levels of genetic differentiation compared to anonymous markers.
• Transcriptome markers proved more effective in identifying subtle population genetic differences.

Conclusions:

• White sharks exhibit restricted gene flow across the Pacific Ocean.
• Transcriptome-derived microsatellite markers are highly effective for elucidating population genetic structure in highly mobile marine species.
• These findings have significant implications for the conservation genetics and biodiversity management of white sharks.