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Male-killing selfish cytoplasmic element causes sex-ratio distortion in Drosophila melanogaster

H Montenegro1, W N Souza, D da Silva Leite

  • 1Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, UNICAMP, Campinas, CEP 13083-970, Sao Paulo, Brazil.

Heredity
|December 21, 2000
PubMed

Insights

A male-killing agent causes sex ratio distortion in Drosophila melanogaster by inducing male mortality before hatching. This maternally inherited, infectious, and cytoplasmic trait was discovered in Brazil.

Area of Science:

  • * Genetics and evolutionary biology.
  • * Microbial-induced speciation and host-pathogen interactions.

Background:

  • * Sex ratio distortion, a phenomenon where the expected 1:1 sex ratio is altered, can significantly impact insect populations.
  • * Maternally inherited microorganisms are known to cause such distortions in various insect species.

Purpose of the Study:

  • * To investigate the cause and inheritance pattern of a newly discovered sex ratio distortion in Drosophila melanogaster.
  • * To determine the stage of male mortality and the mode of transmission of the causative agent.

Main Methods:

  • * Mating experiments with affected flies and marked strains (e.g., white mutation).
  • * Transmission studies via injection of fly macerates.
  • * Pre-adult viability experiments.

Main Results:

  • * The sex ratio distortion is maternally inherited, cytoplasmic, and infectious.
  • * Male mortality occurs before hatching, leading to a skewed sex ratio.
  • * Males do not transmit the trait to their offspring.

Conclusions:

  • * A maternally inherited, infectious, cytoplasmic agent is responsible for sex ratio distortion in this Drosophila melanogaster population.
  • * The agent causes male-specific lethality during embryonic development.
  • * This finding has implications for understanding reproductive strategies and population dynamics in insects.

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