Viruses as environmental mutagenic factors.

Area of Science:

• Genetics
• Virology
• Molecular Biology

Background:

• Exogenous DNA can be mutagenic.
• Viruses contain nucleic acids (DNA or RNA) and proteins.

Purpose of the Study:

• To investigate the mutagenic potential of non-infectious viruses in Drosophila melanogaster.
• To determine if viral nucleic acids or proteins are responsible for mutagenesis.
• To assess the implications for human hereditary defects and biotechnology.

Main Methods:

• Injection of 9 different DNA- and RNA-containing viruses into Drosophila melanogaster males.
• Observation and analysis of induced mutations, including gene mutations, microdeletions, and chromosome rearrangements.

Main Results:

• All tested viruses demonstrated high mutagenicity, inducing numerous gene mutations and microdeletions but no gross chromosome rearrangements.
• Mutagenic effects were locus-specific and varied between viruses, with extraordinarily high mutation rates at affected loci.
• Viral nucleic acids (DNA or cDNA) were identified as the mutagenic agents; viral proteins were not mutagenic.
• Virus-induced mutations likely result from insertions of viral genetic material into host chromosomes, with some mutations exhibiting transpositions and reversions.
• Chromosome aberrations appeared secondary to metabolic disturbances in infected cells.

Conclusions:

• Viruses, particularly apathogenic strains and live viral vaccines, may contribute significantly to hereditary defects in humans.
• Development of purely proteinaceous viral vaccines, free from nucleic acids, is crucial for genetic safety.
• The mutagenic hazards of viruses must be considered in the development of recombinant DNA technologies.