Question

Distinguish between inbreeding and outbreeding.

Answer 1

Hint: The process by which we humans use animals or plants to selectively develop a particular phenotypic trait is called selective breeding. The male and female used for breeding may be closely or distantly related genetically.

Complete answer:
We know that animal breeding is done to obtain some desirable characters in one organism. For this to occur, we should know which exact characters are found in which species. The two organisms i.e. male and female selected may be closely related or distantly related. Based on this, there are two types of selective breeding seen. Their properties and the differences between them are as follows:

Inbreeding	Outbreeding
Breeding is done between two organisms which are closely related genetically and, in most cases, have a common ancestor.	Breeding is done between two organisms which are distantly related genetically and do not have a common ancestor.
Inbreeding increases homozygosity and hence favors the production of pure lines. This makes it the most used technique to develop pure lines.	Outbreeding produces new organisms with all the desirable characteristics and hence it eliminates pure characters.
The biggest disadvantage of inbreeding is, after a certain point it results in ‘inbreeding depression’ which reduces the survival rate and reproduction power significantly.	Similar to inbreeding depression, after the production of several generations, outbreeding depression also occurs which drastically reduces reproductive fitness.
It is mostly seen occurring naturally in flowers which show self-pollination.	Mendel used the method of outbreeding in his experiments with pea plants.

Note:
- Breeding, as the name suggests, occurs between the same ‘breeds’ of an organism. For example, mating a jersey cow with a pure Indian breed cow but we cannot mate a horse with a cow.
- Outbreeding between populations that are adapted to different environmental conditions or with chromosomal incompatibilities can also increase extinction risk.