In biology, a klepton (abbr. kl.) and synklepton (abbr sk.) is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

that requires input from another biological

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

(normally from a species which is closely related to the kleptonic species) to complete its reproductive cycle. Specific types of kleptons are ''zygokleptons'', which reproduce by zygogenesis; ''gynokleptons'' which reproduce by

gynogenesis Gynogenesis, a form of parthenogenesis, is a system of asexual reproduction that requires the presence of sperm without the actual contribution of its DNA for completion. The paternal DNA dissolves or is destroyed before it can fuse with the egg. Th ...

, and ''tychokleptons'', which reproduce by a combination of both systems. Kleptogenic reproduction results in three potential outcomes. A unisexual female may simply activate cell division in the egg through the presence of a male's sperm without incorporating any of his genetic material—this results in the production of clonal offspring. The female may also incorporate the male's sperm into her egg, but can do so without excising any of her genetic material. This results in increased

ploidy Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Sets of chromosomes refer to the number of mat ...

levels that range from

triploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

pentaploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

in wild individuals. Finally, the female also has the option of replacing some of her genetic material with that of the male's, resulting in a "hybrid" of sorts without increasing ploidy.

Etymology

The term is derived from the (Ancient or Modern)

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

κλέπτ(ης) (klépt(ēs), “thief”) + -on, after

, or ''kleptein'', "to steal". A klepton "steals" from an exemplar of another species in order to reproduce. In a paper entitled "Taxonomy of Parthogenetic Species of Hybrid Origin" argues that the thief motif closely parallels the behaviour of certain reptiles.

Examples

Salamander species

In the wild, five species of '' Ambystoma'' salamanders contribute to a unisexual complex that reproduces via a combination of gynogenesis and kleptogenesis: ''A. tigrinum'', ''A. barbouri'', ''A. texanum'', ''A. jeffersonium'', and ''A. laterale''. Over twenty genomic combinations have been found in nature, ranging from "LLJ" individuals (two ''A. laterale'' and an ''A. jeffersonium'' genome) to "LJTi" individuals (an ''A. laterale'', ''A. jeffersonium'', and an ''A. tigrinum'' genome). Every combination, however, contains the genetic information from the ''A. laterale'' species, and analysis of mitochondrial DNA has indicated that these unisexual species most likely diverged from an ''A. barbouri'' individual some 5 million years ago, making them the oldest known unisexual vertebrate species. The fact that these salamanders have persisted for so long is remarkable, as it contradicts the notion that a majority of asexual lineages arise when the conditions are right and quickly disappear. It has been argued that this persistence is very much due to the aforementioned "genome replacement" strategy that accompanies kleptogenic reproduction—replacing a portion of the maternal genome with paternal DNA in offspring has allowed unisexual individuals to "refresh" their genetic material through time. This facet of kleptogenesis was recently ascertained from genetic research that indicates there is no ancestral ''A. laterale'' genome that is maintained from one unisexual to the next, and that there is not a specific "L" genome that is found more often than others. "L" genetic material found in these salamanders has also not evolved to be substantially unique from sexual genomes. In 2007 Bogart et al found that, within a population, unisexual and sexual individuals are able to co-exist; that the genetic makeup of the unisexuals is highly variable; and that unisexual individuals share

alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

with sexual individuals.

Frog species

Other species exhibiting the property include European water frogs of the genus ''

Pelophylax ''Pelophylax'' is a genus of true frogs widespread in Eurasia, with a few species ranging into northern Africa. This genus was erected by Leopold Fitzinger in 1843 to accommodate the green frogs of the Old World, which he considered distinct f ...

''.

Fish species

The Amazon Molly ''(

Poecilia formosa ''Poecilia'' is a genus of fishes in the family Poeciliidae of the order Cyprinodontiformes. These livebearers are native to fresh, brackish and salt water in the Americas, and some species in the genus are euryhaline. A few have adapted to livi ...

)'' exhibits gynogenesis.

References