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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]
As such, there are over 80 species of unisex reptiles (mostly lizards but including a single snake species), amphibians and fishes in nature for which males are no longer a part of the reproductive process. [41] A female produces an ovum with a full set (two sets of genes) provided solely by the mother.
When the female sand lizard Lacerta agilis mates with two or more males, sperm competition within the female's reproductive tract may occur. Active selection of sperm by females appears to occur in a manner that enhances female fitness. [42]
The New Mexico whiptail (Aspidoscelis neomexicanus) is a female-only species of lizard found in New Mexico and Arizona in the southwestern United States, and in Chihuahua in northern Mexico. It is the official state reptile of New Mexico. [2] It is one of many lizard species known to be parthenogenetic.
The desert grassland whiptail lizard (Aspidoscelis uniparens) is an all-female species of reptiles in North America. It was formerly placed in the genus Cnemidophorus. A common predator of the whiptail lizard is the leopard lizard that preys on A. uniparens by using ambush and stalk hunting tactics. [2] [3] [4] These reptiles reproduce by ...
Sperm storage organs in the fruit fly Drosophila melanogaster.Female was first mated with GFP-male and then re-mated with RFP-male. Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized.
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
The lizards were female in appearance and were capable of bearing offspring, despite having the ZZ chromosomes usually associated with male lizards. [ 19 ] In 2018, a team of Chinese and American researchers showed that the histone H3 lysine 27 (H3K27) demethylase KDM6B (JMJD3), an epigenetic modifier, activates male development in red-eared ...