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Genetic incompatibility describes the process by which mating yields offspring that are nonviable, prone to disease, or genetically defective in some way. In nature, animals can ill afford to devote costly resources for little or no reward, ergo, mating strategies have evolved to allow females to choose or otherwise determine mates which are more likely to result in viable offspring.
Spontaneous mutations often occur which can cause various changes in the genome. [28] Mutations can either change the identity of one or more nucleotides, or result in the addition or deletion of one or more nucleotide bases. Such changes can lead to a frameshift mutation, causing the entire code to be read in a different order from the ...
The Black Queen hypothesis is a theory of reductive evolution that suggests natural selection can drive organisms to reduce their genome size. [37] In other words, a gene that confers a vital biological function can become dispensable for an individual organism if its community members express that gene in a "leaky" fashion.
These features normally disappear in later development, but it may not happen if the animal has an atavism. [ 1 ] [ 2 ] In biology , an atavism is a modification of a biological structure whereby an ancestral genetic trait reappears after having been lost through evolutionary change in previous generations. [ 3 ]
However, there are several mechanisms that lead to an unequal transmission of parental alleles from parents to offspring. One example is a gene drive complex, called a segregation distorter , that "cheats" during meiosis or gametogenesis and thus is present in more than half of the functional gametes.
Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles (snakes and lizards). [1]
For the advantage due to genetic variation, there are three possible reasons this might happen. First, sexual reproduction can combine the effects of two beneficial mutations in the same individual (i.e. sex aids in the spread of advantageous traits) without the mutations having to have occurred one after another in a single line of descendants.
Animal reproduction occurs by two modes of action, including both sexual and asexual reproduction. [1] In asexual reproduction the generation of new organisms does not require the fusion sperm with an egg. [1] However, in sexual reproduction new organisms are formed by the fusion of haploid sperm and eggs resulting in what is known as the ...