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Time course imaging of two maize inbreds and their F1 hybrid (middle) exhibiting heterosis. Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents
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.
Darwin's wife, Emma, was his first cousin, and he was concerned about the impact of inbreeding on his ten children, three of whom died at age ten or younger; three others had childless long-term marriages. [16] [17] [18] Humans do not seek to completely minimize inbreeding, but rather to maintain an optimal amount of inbreeding vs. outbreeding.
The divergence between the (two) parent lines promotes improved growth and yield characteristics in offspring through the phenomenon of heterosis ("hybrid vigour" or "combining ability"). Two populations of breeding stock with desired characteristics are subjected to inbreeding until the homozygosity of the population exceeds a certain level ...
Assume the same basic parameters for the life table as given for the haploid case, but distinguishing between male and female, such as N 0 ƒ and N 0 m for the number of newborn females and males, respectively (notice lower case ƒ for females, compared to upper case F for inbreeding). The inbreeding effective number is
A review of the genetics of inbreeding depression in wild animal and plant populations, as well as in humans, led to the conclusion that inbreeding depression and its opposite, heterosis (hybrid vigor), are predominantly caused by the presence of recessive deleterious alleles in populations. [7]
A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection.Meanwhile, low genetic diversity (see inbreeding and population bottlenecks) can cause reduced biological fitness and an increased chance of extinction, although as explained by genetic drift new genetic variants, that may cause an increase in the ...
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. [1] The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously on different traits. [2]