Homologue destabilization by a putative transposable element in Drosophila melanogaster

Area of Science:

• Genetics
• Molecular Biology
• Chromosomal Instability

Background:

• Unstable X chromosomes exhibit high rates of recessive lethal mutations.
• A stable X chromosome associated with an unstable one also becomes mutable.

Purpose of the Study:

• To identify the genetic element responsible for X chromosome instability and high mutation rates.
• To elucidate the mechanism of "homologue destabilization".

Main Methods:

• Observational studies of X chromosome properties and mutation rates.
• Genetic analysis to track the inheritance and effects of the unstable element.
• Cytogenetic analysis of chromosome aberrations.

Main Results:

• A transposable element, the L factor, is postulated to cause instability.
• The L factor appears confined to the X chromosome and transposes to homologous chromosomes.
• Lethal mutations and chromosome aberrations preferentially occur near the cut wing (ct) locus.

Conclusions:

• The L factor is responsible for X chromosome instability and "homologue destabilization".
• The L factor's preferential targeting of the ct region suggests a specific insertion site or preferred target region.