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A mule is a sterile hybrid of a male donkey and a female horse.Mules are smaller than horses but stronger than donkeys, making them useful as pack animals.. In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction.
The sterility of many interspecific hybrids in angiosperms has been widely recognised and studied. [33] Interspecific sterility of hybrids in plants has multiple possible causes. These may be genetic, related to the genomes, or the interaction between nuclear and cytoplasmic factors, as will be discussed in the corresponding section.
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 ...
Sterility is the inability to produce a biological child, while infertility is the inability to conceive after a certain period. [1] Sterility is rarely discussed in clinical literature and is often used synonymously with infertility. Infertility affects about 12-15% of couples globally. [2] Still, the prevalence of sterility remains unknown.
Cytoplasmic male sterility is also used in hybrid seed production. In this case, male sterility is maternally transmitted and all progeny will be male sterile. These CMS lines must be maintained by repeated crossing to a sister line (known as the maintainer line) that is genetically identical except that it possesses normal cytoplasm and is ...
Working in the early 20th century T.H. Morgan, was the first to use Drosophila to explore heredity. Primarily on the basis of work with D. melanogaster, Morgan and his colleagues C.B. Bridges, A.H. Sturtevant, and H.J. Mueller developed a chromosome theory of heredity, for which Morgan was awarded a Nobel Prize in 1933.
When two populations diverge from each other and encounter new - and different - environments they may adapt to these environments. These adaptations can result in hybrid sterility as a side effect. The genes that have arisen to adapt to different ecological surroundings can thus cause hybrid incompatibilities.
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 ...