Question

What is variation and its types?

Answer 1

Variation:

1. Variations are the differences in the genetic makeup or phenotype of various organisms.
2. Variation arises due to crossing over, recombination, mutation & environmental effects on the expression of genes present on chromosomes.

Types of variation

Somatogenic Variations:

1. These are variations that affect the somatic or body cells of the organisms.
2. They are also called the modifications or acquired characters since they are acquired by the individual during its lifetime.

Factors causing it are:

1. Environment: The environmental factors are the medium, light, temperature, nutrition, wind, water supply, etc. Such environmental factors bring about changes in the phenotype of the individual.
2. Use and disuse of organs: The organ that is put to continuous use develops more while the organ less used develops little.
3. Conscious efforts: Modifications that occur due to conscious efforts are observed only in those animals that have intelligence. Receiving education, training of some pets, slim bodies, boring of the pinna, long neck, small feet, mutilations in pets, etc. are some of the examples of conscious efforts.

Germinal or Blastogenic Variations:

1. They are produced in germ cells of an organism & are inheritable.
2. They may be already present in the ancestors or may be formed suddenly.
3. Horn is the character of cattle whose expression is based on the expression of the gene related to the horns.
4. If such genes of horn get suppressed in some cattle, then the cattle become hornless.