Heritable Genetic Effects Caused by a Single Generation of Captive Breeding

Area of Science:

• Aquatic genetics
• Conservation biology
• Fisheries science

Background:

• Captive breeding is crucial for fisheries management and conservation.
• Genetic adaptation to captivity can reduce wild fitness in a single generation.
• Understanding these genetic changes is vital for effective conservation strategies.

Purpose of the Study:

• To investigate the genetic effects of one generation of captive breeding on steelhead (Oncorhynchus mykiss).
• To identify global gene expression patterns associated with rapid adaptation to captivity.

Main Methods:

• Performed crosses between first-generation hatchery and natural-origin steelhead.
• Raised offspring in a common environment.
• Utilized RNA-sequencing (RNA-seq) to analyze gene expression patterns.

Main Results:

• Identified hundreds of differentially expressed genes (DEGs) after one generation in captivity.
• The majority of DEGs (75%) were upregulated in offspring of first-generation hatchery fish.
• DEGs were primarily associated with growth, development, behavior, immune response, and metabolism.
• Reciprocal crosses ruled out maternal/paternal effects or background expression differences.

Conclusions:

• A single generation of captive breeding induces significant, heritable genetic changes in steelhead.
• These changes manifest as widespread alterations in gene expression.
• Findings have critical implications for stocking and reintroduction programs in fisheries management.