Mitochondrial DNA is unsuitable to test for isolation by distance

Area of Science:

• Population Genetics
• Molecular Ecology
• Conservation Biology

Background:

• Isolation by distance (IBD) is a key metric for understanding spatial genetic structure.
• Mitochondrial DNA (mtDNA) is frequently used for IBD studies but can conflict with other genetic markers.
• Discrepancies between mtDNA and multilocus markers raise questions about mtDNA's reliability in IBD assessments.

Purpose of the Study:

• To review literature on IBD and assess if significant findings result from pooling discrete populations.
• To determine if microsatellite markers are more effective than mtDNA in detecting IBD.
• To empirically test mtDNA's efficacy against microsatellite and SNP data in four species.

Main Methods:

• Literature review of isolation by distance (IBD) studies.
• Comparative analysis of genetic markers (mtDNA, microsatellites, SNPs).
• Empirical data collection and analysis from four distinct species.

Main Results:

• Significant IBD is often an artifact of analyzing pooled, discrete populations.
• Discrepancies between mtDNA and multilocus markers were noted in nearly half of reviewed studies.
• Microsatellite and SNP data provided stronger support for IBD than mtDNA, particularly in empirical tests.

Conclusions:

• Mitochondrial DNA (mtDNA) sequence data are often unsuitable and can be misleading for testing isolation by distance (IBD).
• Microsatellite and SNP markers are more reliable for assessing spatial genetic structure and species' dispersal potential.
• Pooling discrete populations can artificially inflate IBD signals, necessitating careful population delineation in genetic studies.