This article discusses the conservation implications of inbreeding and outbreeding depression. AB - Inbreeding refers to mating of related individuals. Department of Biological Sciences. Overview Fingerprint. Abstract Inbreeding refers to mating of related individuals. Fingerprint Dive into the research topics of 'Inbreeding and outbreeding'. Together they form a unique fingerprint. Closely related individuals such as siblings are selected for inbreeding. The progeny of inbreeding will show increased homozygosity.
The main objective of inbreeding is to maintain desirable traits and eliminate undesirable traits from that population. However, inbreeding can result in a higher chance of expressing deleterious recessive mutations as shown in figure Hence, there is a high probability in offspring of carrying deleterious recessive traits due to the increased homozygosity by inbreeding.
This introduces the lower fitness levels in the progeny of inbreeding. This phenomenon is known as inbreeding depression. When inbreeding produces biologically offspring with lower fitness, they are unable to survive and reproduce. Hence the offspring with high homozygosity are easily prone to becoming extinct from the environment by natural selection ; this is known as genetic purging. Inbreeding is a breeding method used in selective breeding to develop a particular phenotypic trait in plants and animals by making pure lines.
Figure Inbreeding of pony — An example of inbreeding depression. Outbreeding, also known as outcrossing, is a process of mating distantly related or unrelated two individuals. The selection of two individuals is made from two populations. The main objective of outbreeding is to produce offspring with superior characteristics or quality.
These two individuals are phenotypically adapted to two different environments. Therefore the progeny of the outcross may not easily adapt to live in either environment because the outcross might produce the phenotype intermediate to the parents.
It will not perfectly suit for the parental environments. Hence, outbreeding does not always produce increased fitness in offspring. Sometimes outbreeding can show lower fitness to withstand the parental environment. It is known as outbreeding depression.
In most occasions, outbreeding produces offspring with superior quality. The mixing of genomes of two different populations may result in offspring which is superior to either of its parents. This is known as outbreeding enhancement and increases the genetic variation of the new genome.
This increased genetic variation becomes beneficial in order to protect from extinction due to various factors such as environmental stress. The mixing of genes between two unrelated individuals, also increases the masking effects of deleterious mutations occur by recessive alleles. Inbreeding depression is another disadvantage; this reduces the biological fitness of the population, reducing the ability of the offspring to survive and reproduce may occur. Outbreeding or outcrossing refers to a breeding method that involves unrelated organisms.
As outbreeding combines the characteristics of different pure breeds, it increases the variation of a group of organisms through mating. The breeding of individuals in two populations of the same genus is an example of outbreeding. Outbreeding makes more heterozygous allele combinations within the offspring, randomly mixing all the possible alleles found in the population.
Outbreeding depression is the main disadvantage of outbreeding in which the production of unsuitable traits for the present habitat is produced that reduces the fitness to the environment. Genetic variation of different human populations is shown in figure 2. Figure 2: Genetic Variation in Human Population. Interbreeding refers to the breeding involving individuals of different varieties of organisms that belong to the same genus. Some characteristics such as vigour of the offspring are hybrid in both outbreeding and interbreeding.
Therefore, the offspring is referred to a hybrid. A hybrid has more beneficial traits than its either parent. Inbreeding: Inbreeding is the production of offspring from the breeding of organisms that are closely related genetically. Outbreeding: Outbreeding is the production of offspring from the breeding of organisms that are genetically unrelated. Inbreeding: Closely-related organisms are used in inbreeding.
Outbreeding: Unrelated organisms are used in the outbreeding. Inbreeding: Parents used for inbreeding are the same breed for generations.
Outbreeding: Parents used for outbreeding should not be the common ancestor for generations. Inbreeding: Mating occurs between individuals of the same species in inbreeding.
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