Genotype-by-environment interactions for seminal fluid expression and sperm competitive ability.

Area of Science:

• Evolutionary biology
• Reproductive strategies
• Genetics

Background:

• Sperm competition arises from female multiple mating, impacting male reproductive success.
• Sperm competitive ability is influenced by genetic and environmental factors, including genotype-by-environment interactions (GEI).
• Seminal fluid plays a key role in mediating sperm competition, with gene expression potentially varying based on competition levels.

Purpose of the Study:

• To investigate GEI in the expression of seminal fluid transcripts (suckless-1 and suckless-2) in Macrostomum lignano.
• To test for GEI in sperm competitive ability within this species.
• To determine the relationship between natural variation in seminal fluid transcript expression and relative paternity success.

Main Methods:

• Analysis of GEI in the expression of suckless-1 and suckless-2 transcripts.
• Standardized sperm competition assays (P1 and P2) to measure competitive ability.
• Correlation analysis between seminal fluid gene expression and paternity outcomes.

Main Results:

• Significant GEI was detected for the expression levels of both suckless-1 and suckless-2.
• GEI also influenced sperm competitive ability in the assays.
• A positive correlation was observed between suckless-1 expression and relative paternity success (P1).

Conclusions:

• Natural variation in seminal fluid transcript expression, driven by GEI, can impact sperm competition outcomes.
• The suckless-1 transcript is a potential mediator of paternity success in Macrostomum lignano.
• These findings highlight the complex interplay of genetics and environment in shaping reproductive strategies.