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Animals avoid inbreeding only rarely. [2] Inbreeding results in homozygosity which can increase the chances of offspring being affected by recessive traits. [3] In extreme cases, this usually leads to at least temporarily decreased biological fitness of a population [4] [5] (called inbreeding depression), which is its ability to survive and ...
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.
The coefficient of inbreeding (COI) is a number measuring how inbred an individual is. Specifically, it is the probability that two alleles at any locus in an individual are identical by descent from a common ancestor of the two parents.
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 ]
The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy.
In 1995, there was a reported case of partial human parthenogenesis; a boy was found to have some of his cells (such as white blood cells) to be lacking in any genetic content from his father. Scientists believe that an unfertilized egg began to self-divide but then had some (but not all) of its cells fertilized by a sperm cell; this must have ...
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).
Thus, assuming that in any one generation all levels of inbreeding are the same, these two coefficients of parentage each represent (1/2) [1 + f (t-2)] . Inbreeding from full-sib and half-sib crossing, and from selfing. Now, examine f AB. Recall that this also is f P1 or f P2, and so represents their generation - f (t-1).