Ancestral population reconstitution from isofemale lines as a tool for experimental evolution

Area of Science:

• Evolutionary Biology
• Genetics
• Population Genetics

Background:

• Experimental evolution is crucial for studying adaptation under controlled conditions.
• Measuring adaptation often relies on comparing evolved populations to unselected references, but this can be biased by laboratory adaptation and genetic drift.
• Ancestral variation can be preserved in isofemale lines for reconstituting ancestral populations.

Purpose of the Study:

• To assess the impact of selection on segregating alleles within newly established Drosophila isofemale lines.
• To validate the use of ancestral population reconstitution from isofemale lines as an unbiased method for measuring adaptation.

Main Methods:

• Reconstitution of two ancestral populations (AP) from isofemale lines.
• Comparison of reconstituted APs with original APs founded shortly after collection.
• Simulations to assess the impact of genetic drift and sampling effects.

Main Results:

• No significant allele frequency changes were detected between reconstituted and original ancestral populations.
• Simulations indicated that genetic drift had a low impact compared to Pool-Seq sampling effects.
• Laboratory selection on segregating variation in isofemale lines was found to be too weak for detectable effects.

Conclusions:

• Ancestral population reconstitution from isofemale lines is a valid and unbiased approach for measuring adaptation.
• Experimental evolution studies can confidently use this method to avoid biases associated with laboratory adaptation and drift.