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Inbreeding is also used to reveal deleterious recessive alleles, which can then be eliminated through assortative breeding or through culling. In plant breeding, inbred lines are used as stocks for the creation of hybrid lines to make use of the effects of heterosis. Inbreeding in plants also occurs naturally in the form of self-pollination.
Mixed mating systems are generally characterized by the frequency of selfing vs. outcrossing, but may include the production of asexual seeds through agamospermy. [2] The trade offs for each strategy depend on ecological conditions, pollinator abundance and herbivory [ 3 ] and parasite load. [ 4 ]
In plants, selfing can occur as autogamous or geitonogamous pollinations and can have varying fitness affects that show up as autogamy depression. After several generations, inbreeding depression is likely to purge the deleterious alleles from the population because the individuals carrying them have mostly died or failed to reproduce.
Therefore the coefficient of inbreeding of individual G is = (+) = + = %. If the parents of an individual are not inbred themselves, the coefficient of inbreeding of the individual is one-half the coefficient of relationship between the parents. This can be verified in the previous example, as 12.5% is one-half of 25%, the coefficient of ...
Sequential hermaphroditism can also protect against inbreeding in populations of organisms that have low enough motility and/or are sparsely distributed enough that there is a considerable risk of siblings encountering each other after reaching sexual maturity, and interbreeding.
A coefficient of inbreeding can be calculated for an individual, and is typically one-half the coefficient of relationship between the parents. In general, the higher the level of inbreeding the closer the coefficient of relationship between the parents approaches a value of 1, expressed as a percentage, [ a ] and approaches a value of 0 for ...
However, when genetically similar SI cultivars are bred, inbreeding depression can cause a cross-incompatible form of SC to arise, such as in apricots and almonds. [ 57 ] [ 58 ] In this rare, intraspecific, cross-incompatible mechanism, individuals have more reproductive success when self-pollinated rather than when cross-pollinated with other ...
Genetic purging is the increased pressure of natural selection against deleterious alleles prompted by inbreeding. [1]Purging occurs because deleterious alleles tend to be recessive, which means that they only express all their harmful effects when they are present in the two copies of the individual (i.e., in homozygosis).