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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]
A form of asexual reproduction related to parthenogenesis is gynogenesis. Here, offspring are produced by the same mechanism as in parthenogenesis, but with the requirement that the egg merely be stimulated by the presence of sperm in order to develop. However, the sperm cell does not contribute any genetic material to the offspring.
Mucor (short for Mucormycosis) is a microbial genus of approximately 40 species of molds in the family Mucoraceae. [ 1 ] [ 2 ] Species are commonly found in soil , digestive systems , plant surfaces, some cheeses like Tomme de Savoie , rotten vegetable matter and iron oxide residue in the biosorption process.
Asexual reproduction is found in nearly half of the animal phyla. [57] Parthenogenesis occurs in the hammerhead shark [ 58 ] and the blacktip shark . [ 59 ] [ 60 ] In both cases, the sharks had reached sexual maturity in captivity in the absence of males, and in both cases the offspring were shown to be genetically identical to the mothers.
Asexual reproduction often occurs continuously. In heterothallic species, sexual reproduction occurs when opposite mating types (designated + and -) come into close proximity, inducing the formation of specialized hyphae called gametangia. The gametangia grow toward each other, then fuse, forming a diploid zygote at the point of fusion.
Known reproduction states of Mucoromycota are zygospore production and asexual reproduction. Zygospores can have decorations on their surface and range up to several millimeters in diameter. [ 13 ] Asexual reproduction typically involves the production of sporangiospores or chlamydospores . [ 3 ]
As predicted, sexual reproduction dominates in shallow water, due to its advantages in parasite resistance. Asexual reproduction is dominant in the deeper water of lakes, as the scarcity of parasites means that the advantages of resistance are outweighed by the costs of sexual reproduction. [54] Each female can produce between 20 and 120 ...
With the exception of a few purely asexual species, the lifecycle of diplostracans is dominated by asexual reproduction, with occasional periods of sexual reproduction; this is known as cyclical parthenogenesis. [11] When conditions are favourable, reproduction occurs by parthenogenesis for several generations, producing only female clones. As ...