Phylogenetic relationships between parthenogens and their sexual relatives: the possible routes to parthenogenesis in animals

Abstract

In theory, parthenogenetic lineages have low evolutionary potential because they inexorably accumulate deleterious mutations and do not generate much genotypic diversity. As a result, most parthenogenetic taxa occupy the terminal nodes of phylogenetic trees. The rate and mode of development of parthenogenesis are important factors to consider when assessing its costs and benefits since they determine both the level of genetic diversity and the ecological adaptability of the resulting lineages. The origin of parthenogenesis is polyphyletic in many taxa, suggesting that genetic systems maintaining sexuality are often labile. In addition, the loss of sex may be achieved in several ways, leading to parthenogenetic lineages with distinct genetic profiles. This could then influence not only the fate of such lineages in the long term, but also the outcome of competition with their sexual counterparts in the short term. In this paper, we review the possible evolutionary routes to parthenogenesis based on a survey of the phylogenetic relationships between sexual and parthenogenetic lineages in a broad range of animals. We also examine the different mechanisms by which parthenogenetic lineages could arise, and discuss the influence of these mechanisms on both the genetic properties and the ecological life styles of the resulting lineages. © 2003 The Linnean Society of London. Biological Journal of the Linnean Society, 2003, 79, 151–163.

Genetic variability and adaptive evolution in parthenogenetic root-knot nematodes

“…Molecular studies have nevertheless confirmed that the apomictic RKN species share a common lineage, and that they diverged early from meiotic species (Castagnone-Sereno et al, 1993b;Baum et al, 1994). There are several ways in which parthenogenetic lineages could arise (Simon et al, 2003). In the case of RKN, no fossil records are available, and the ancestors of the genus are unknown.…”

Different aspects of reproduction strategies in crayfish: A review

“…Hybridization may have occurred both in nature and in the aquarium. Parthenogenesis of a contagious origin, that is the hybridization of females from a pre-existing parthenogenetic lineage with males of either the same or a closely related species, is common in brine shrimp and ostracods and generally results in polyploid unisexuals (Simon et al, 2003). The critically endangered hairy marron, Cherax tenuimanus, an endemic species in the Margaret River, Western Australia, is being rapidly replaced by the invasive smooth marron, C. cainii (Bunn et al, 2008).…”

Thelytokous parthenogenesis in the damselfly Ischnura hastata (Odonata, Coenagrionidae): genetic mechanisms and lack of bacterial infection

“…Different ways have been described, in which parthenogenetic lineages may originate from sexual species (reviewed in Simon et al, 2003). The majority of the cases of parthenogenesis studied today are associated with bacterial infections.…”

“…Such mutations may result in the establishment of an obligate parthenogenetic lineage, or may also initiate a lineage in which a small proportion of females has the potential for parthenogenetic reproduction, which in turn will provide for the possibility to select for parthenogenesis in the laboratory and in nature (Templeton, 1982;Kramer and Templeton, 2001). Spontaneous origins of parthenogenesis have been shown in a wide range of invertebrates, including snails, ostracods, crustaceans and insects (reviewed in Simon et al, 2003). Tychoparthenogenesis refers to the occasional, spontaneous development of eggs without fertilization in otherwise sexually reproducing species, a form of reproduction which is characterized by a low-hatching success of unfertilized eggs (White, 1973;Bell, 1982;Suomalainen et al, 1987).…”

“…An alternative route to parthenogenesis in animals is the spontaneous loss of sex through mutations in the genes involved in the production of sexual forms (Simon et al, 2003), or in genes related to mating behaviour and successful egg fertilization (Carson et al, 1982). Such mutations may result in the establishment of an obligate parthenogenetic lineage, or may also initiate a lineage in which a small proportion of females has the potential for parthenogenetic reproduction, which in turn will provide for the possibility to select for parthenogenesis in the laboratory and in nature (Templeton, 1982;Kramer and Templeton, 2001).…”