Invasion of the hybrids

Area of Science:

• Evolutionary Biology
• Genetics
• Ecology

Background:

• Human activity and climate change are increasing interspecies hybridization.
• Hybridization combines genomes from diverged species, potentially creating novel adaptive traits.
• Invasive hybrid swarms can exploit new environmental niches.

Purpose of the Study:

• To investigate the genetic and transcriptional changes associated with hybridization in invasive sculpins (Cottus).
• To differentiate the roles of admixture versus post-hybridization selection in invasive success.
• To understand the genetic basis of transgressive segregation in hybrid species.

Main Methods:

• Gene expression microarray assays were used to compare gene expression.
• Expression profiles of wild and lab-reared invasive hybrids were compared to progenitor species.
• Experimentally produced F(2) hybrids were analyzed.

Main Results:

• Hybridization alone increases gene expression variance, including transgressive segregation.
• Many transgressive changes in invasive sculpins occurred after the initial hybridization event.
• Initial hybrid success is facilitated by hybridization, followed by selection that reduces expression variation.

Conclusions:

• While hybridization initiates phenotypic variation, subsequent selection refines the invasive phenotype.
• The invasive success of sculpins is a result of both hybridization and post-hybridization adaptive evolution.
• Understanding these processes is crucial for managing invasive hybrid species.