Peripheral Budding Following Range Expansion Explains Diversity and Distribution of One-Sided Livebearing Fish.

Area of Science:

• Evolutionary Biology
• Genomics
• Speciation Research

Background:

• Peripheral budding describes speciation from a widespread parental population, often leading to distinct range sizes and complex phylogenies.
• The Jenynsia lineata species complex exhibits characteristics of peripheral budding, including asymmetric range sizes and an unresolved phylogenetic history.

Purpose of the Study:

• To classify the Jenynsia lineata species complex using genomic data.
• To delimit species within the complex and identify introgression patterns.
• To understand the evolutionary mechanisms, specifically peripheral budding, driving speciation in this fish group.

Main Methods:

• Genomic analysis of 85 Jenynsia lineata samples.
• RAD sequencing to generate genome-wide molecular markers.
• Phylogenetic analyses to reconstruct evolutionary relationships.

Main Results:

• Identification of six distinct genetic groups within the Jenynsia lineata complex.
• Delimitation of at least five species, including a new species from Northern Argentina.
• Jenynsia lineata identified as the most recently diverged species, with evidence of introgression.

Conclusions:

• Genomic data support peripheral budding as a key mechanism in the speciation of the Jenynsia lineata complex.
• Peripheral budding, following range expansion of a parental Jenynsia lineata, facilitated the diversification of new species.
• This study highlights the utility of genomic approaches in resolving complex phylogenetic patterns shaped by peripheral budding.