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Hybrid inviability is a post-zygotic barrier, which reduces a hybrid's capacity to mature into a healthy, fit adult. [1] The relatively low health of these hybrids relative to pure-breed individuals prevents gene flow between species.
Hybrid incompatibility occurs when the offspring of two closely related species are not viable or suffer from infertility. Charles Darwin posited that hybrid incompatibility is not a product of natural selection, stating that the phenomenon is an outcome of the hybridizing species diverging, rather than something that is directly acted upon by selective pressures. [4]
Although the hybrid may be sterile, it can continue to multiply in the wild by asexual reproduction, whether vegetative propagation or apomixis or the production of seeds. [ 35 ] [ 36 ] [ clarification needed ] Indeed, interspecific hybridization can be associated with polyploidia and, in this way, the origin of new species that are called ...
In humans, barring intersex conditions causing aneuploidy and other unusual states, it is the male that is heterogametic, with XY sex chromosomes.. Haldane's rule is an observation about the early stage of speciation, formulated in 1922 by the British evolutionary biologist J. B. S. Haldane, that states that if — in a species hybrid — only one sex is inviable or sterile, that sex is more ...
Genes that are incompatible according to the Dobzhansky–Muller model require three criteria. 1. The gene reduces the fitness of the hybrid, 2. The gene has functionally diverged in each of the hybridising species and, 3. The hybrid incompatibility is only present in combination with a partner gene. [6]
hybrid inviability hybrid speciation hybrid sterility hybrid swarm hybrid zone A geographic area in which the ranges of two interbreeding species or populations overlap, allowing them to cross-fertilize and generate hybrid offspring. The formation of a hybrid zone is one of the four outcomes of secondary contact between divergent genetic ...
A hybrid security is a single financial product that combines different types of financial securities, or has features of multiple kinds of securities. Typically, this means that the security has ...
Reinforcement, under his definition, included prezygotic divergence and complete post-zygotic isolation. [18] Servedio and Noor include any detected increase in prezygotic isolation as reinforcement, as long as it is a response to selection against mating between two different species. [ 4 ]