Course Content
History of genetics
Learn introductory genetics with Braimy- B.Sc agriculture
About Lesson
  • It is the phenomenon of one gene affecting more than one character.
  • Eg: Sickle cell anemia, white eye gene in Drosophila

a) Lethal gene action:

  • Some time , the pleiotropic gene effect produces various abnormal ability in phenotypic feature which are collectively called syndromes.
  • When the pleiotropic gene cause further death of the individual then it is called lethal gene.
  • This lethal gene is either in a homozygous condition (dominant)or homozygous recessive condition.
  • It is of following types: Dominant lethal. Recessive lethal, conditional lethal, Balanced lethal and gametic lethal.

b) Semi lethal gene action:

  • < 10% individuals survive.
  • Eg: xantha mutants.

c) Vital gene action:

  • Don’t affect the survival of the individuals.
  • Neither enhance nor reduces the viability.

d) Sub vital gene action:

  • Reduces viability.
  • Kill less than 90% individuals .
  • Eg: Mutant species.

e) Super vital gene action:

  • Enhance the survival of the individual.
  • Eg: disease resistance , insect resistance and other resistance.
Join the conversation
Scroll to Top