Complex hybridization between deeply diverged fish species in a disturbed ecosystem

Area of Science:

• Evolutionary Biology
• Genomics
• Conservation Genetics

Background:

• Natural hybridization between species is a widespread evolutionary phenomenon, increasingly studied with genomic tools.
• Complex hybridization, involving more than two species, has been observed across diverse taxa.
• Anthropogenic disturbance may be increasing the frequency of contemporary hybridization events.

Purpose of the Study:

• To develop a novel computational tool for local ancestry inference in hybrids from three distinct parental populations.
• To investigate a recent, complex hybridization event within the swordtail fish genus (Xiphophorus).
• To explore potential connections between this hybridization event and anthropogenic environmental modifications.

Main Methods:

• Development of a flexible local ancestry inference tool designed for admixed genomes from three source populations.
• Application of the tool to analyze genomic data from swordtail fish populations exhibiting signs of recent hybridization.
• Comparative genomic analysis to identify admixture patterns and infer ancestry in hybrid individuals.

Main Results:

• Successful development and validation of a new local ancestry inference tool capable of handling complex, three-way admixture.
• Identification of a recent and complex hybridization event involving distantly related swordtail fish lineages.
• Genomic evidence suggests admixture patterns consistent with recent gene flow between these lineages.

Conclusions:

• The developed tool provides a valuable resource for studying complex hybridization dynamics in natural populations.
• The findings highlight a recent, intricate hybridization event in Xiphophorus, underscoring the role of gene flow in evolution.
• Further research is warranted to elucidate the specific environmental factors, including anthropogenic influences, driving this hybridization.