Sleeping with the enemy: introgressive hybridization in two invasive centrarchids

Area of Science:

• Aquatic Ecology
• Genetics
• Conservation Biology

Background:

• Micropterus dolomieu and Micropterus salmoides are invasive species in South Africa.
• Understanding hybridization is crucial for managing invasive fish populations and native biodiversity.

Purpose of the Study:

• To investigate the extent and direction of introgressive hybridization between M. dolomieu and M. salmoides.
• To assess genetic admixture in their introduced South African range.

Main Methods:

• Analysis of nine microsatellite markers for nuclear DNA assessment.
• Sequencing of two mitochondrial DNA (mtDNA) gene regions to trace maternal lineages.

Main Results:

• Significant genetic differentiation between M. dolomieu and M. salmoides, indicating they are distantly related.
• Detection of mitochondrial introgression, suggesting gene flow from one species to the other's mtDNA.
• Evidence of unidirectional admixture, implying a dominant direction of genetic exchange.

Conclusions:

• Introgressive hybridization is occurring between these two distantly related bass species in South Africa.
• Mitochondrial introgression and unidirectional admixture highlight complex genetic interactions in invasive populations.
• Findings have implications for fisheries management and the conservation of native aquatic ecosystems.