Multispecies coalescent delimits structure, not species

Area of Science:

• Evolutionary Biology
• Genomics
• Computational Biology

Background:

• Species delimitation often uses the multispecies coalescent model.
• Previous studies treated speciation as instantaneous, not a phased process.

Purpose of the Study:

• To assess species delimitation performance using the multispecies coalescent model with simulations of extended speciation.
• To investigate whether the model distinguishes population structure from species boundaries.

Main Methods:

• Simulated data modeling speciation as an extended process.
• Species delimitation inference using the multispecies coalescent model.

Main Results:

• The multispecies coalescent model identifies genetic structure, not species.
• The model fails to differentiate population isolation from species boundaries.
• This can lead to overestimation of species numbers.

Conclusions:

• Genomic data alone may misidentify population structure as species.
• Genome-based species discovery requires validation with phenotypic and ecological data.
• New methods are needed to distinguish population structure from species boundaries.