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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]
In species that use the XY sex-determination system, parthenogenetic offspring have two X chromosomes and are female. In species that use the ZW sex-determination system the offspring genotype may be one of ZW (female), [30] [31] ZZ (male), or WW (non-viable in most species, [33] but a fertile, [dubious – discuss] viable female in a few, e.g ...
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.
Occasionally, a mating between a female of one species and a male of another produces a parthenogen, a female that is able to produce viable eggs that are genetically identical to her own cells. The lizards that hatch from these eggs are thus also parthenogens that can again produce identical eggs, resulting in an asexual, clonal population.
A hemipenis (pl.: hemipenes) is one of a pair of intromittent organs of male squamates (snakes and lizards). [1] [2] [3] Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like that in the human penis. They come in a variety of shapes, depending on species, with ornamentation such as ...
Females in many lizard species have the choice to mate with or reject males. [14] Females spend energy in investigating a male's traits in order to determine if he is healthy and has good genes. [14] In the species Side-blotched lizard (Uta stansburiana), males chosen by females had 76 percent less ectoparasites. [15]
Most organisms that create their offspring using sexual reproduction have two common sexes, males and females, and in other species, there are hermaphrodites, organisms that can function reproductively as either female or male, or both. [2] There are also some species in which only one sex is present, temporarily or permanently.
The lizards reproduce by parthenogenesis and are clones of their mother. Under normal reproductive processes, a species has each chromosome pair separated, copied, and paired back with its counterpart. The desert grassland whiptail lizard, however, has chromosome triplets where each triplet is paired with its copy rather than its counterparts ...