Question

Define outbreeding.

Answer 1

Hint Animal breeding is one of the most important branches of animal husbandry. Breeding includes crossing between different animals so as to improve the desirable qualities. This is done by choosing two animals that have no common ancestors with desirable traits.

Complete answer:
Outbreeding can be defined as a technique that includes crossing between different breeds with no common ancestors. It is also the practice of introducing unrelated genetic material into any breeding line. Outbreeding can be considered as the reverse case of inbreeding, as outbreeding includes the production of offspring through mating between individuals unrelated or distantly related by ancestral descendent. The general advantage of outbreeding is that it promotes an increase in phenotypic variability within a population. This mainly enables different types of plants to adapt to a wider range of environmental conditions and increases their chance of survival and evolutionary change. On the other hand, one disadvantage of outbreeding is that it requires a transfer of gametes between the two different individuals. If individuals are not near, or if pollinators are less, sexual reproduction may not occur at all in obligately outbreeding species.

Additional information:
The three main methods of outbreeding are:-
-Outcrossing: Individuals belonging to similar breeds are mated but these individuals do not have any common ancestors for at least 4-5 generations. This technique is mainly used to reverse the damage of inbreeding depression.
-Crossbreeding: Crossbreeding includes producing offspring by mating purebred individuals of different breeds or varieties. Often, superior males of one breed are mated with the superior females of another breed. This helps in bringing about the desirable qualities of both breeds together. For example, Hisardale sheep which is a cross between Bikaneri ewes and Merino rams.
-Interspecific breeding: Hybrids are bred through mating individuals from two different species, belonging to the same genus. The offspring produced displays the traits and characteristics of both the parents, but are often sterile that prevents gene flow between the species. For example, Mule is a cross between a female horse and a male donkey.

Notes: Outbreeding is known to increase the chances of genetic diversity and introduce elite alleles into the breeding population. Another advantage related to genetic effect of outbreeding is hybrid vigor or heterosis (the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit higher biomass rate, development speed, and fertility than both parents) which is utilized extensively in animal and plant production.