Definition of semi-lethal in English:

semi-lethal

adjective

Genetics
  • Relating to or denoting an allele or chromosomal abnormality which impairs the viability of most of the individuals homozygous for it.

    • ‘A chief difficulty in arguing for macroevolution by mutations is the fact that most expressed mutations are either lethal or semi-lethal.’
    • ‘Some of the genes that gives the mouse its common colours or markings also makes the mouse sick, or unfit to live. These genes are called semi-lethal or lethal.’
    • ‘Pokey (pok), a sex-linked recessive semi-lethal gene in Tribolium castaneum has been described.’