Selection for reduced crossing over in Drosophila melanogaster

Area of Science:

• Genetics
• Evolutionary Biology
• Molecular Biology

Background:

• Crossing over is a fundamental process in meiosis, influencing genetic variation.
• Understanding the regulation of crossing over is crucial for genetic studies.
• Drosophila melanogaster serves as a model organism for genetic research.

Purpose of the Study:

• To investigate the potential for artificial selection to reduce crossing over between two specific genes (Sb and H(2)) on the third chromosome of Drosophila melanogaster.
• To determine if genetic variability exists for controlling recombination frequencies in the studied population.

Main Methods:

• Selection was applied to repulsion double heterozygotes (Sb+/+H(2)) over 24 generations in two replicate lines.
• Recombination values were measured across generations.
• Statistical analysis, including regression analysis, was used to assess changes in recombination frequency and significance.

Main Results:

• One selection line (Line 2) exhibited a significantly lower recombination value compared to the control by generation 20, with a highly significant regression coefficient.
• The other selection line (Line 1) did not show a significant difference from the control, despite a significant regression of recombination value on generation.
• No chromosomal rearrangements were detected, suggesting a genic basis for the observed changes.

Conclusions:

• Substantial genic variability for controlling crossing over frequency between the Sb and H(2) genes exists in the base population.
• Artificial selection can be effective in modifying recombination frequencies, at least in one replicate line.
• The results highlight the role of genetic factors in regulating meiotic recombination.