Functional rare males in diploid parthenogeneticArtemia

Abstract

Functional males that are produced occasionally in some asexual taxacalled 'rare males' -raise considerable evolutionary interest, as they might be involved in the origin of new parthenogenetic lineages. Diploid parthenogenetic Artemia produce rare males, which may retain the ability to mate with females of related sexual lineages. Here, we (i) describe the frequency of male progeny in populations of diploid parthenogenetic Artemia, (ii) characterize rare males morphologically, (iii) assess their reproductive role, using cross-mating experiments with sexual females of related species from Central Asia and characterize the F1 hybrid offspring viability and (iv) confirm genetically both the identity and functionality of rare males using DNA barcoding and microsatellite loci. Our result suggests that these males may have an evolutionary role through genetic exchange with related sexual species and that diploid parthenogenetic Artemia is a good model system to investigate the evolutionary transitions between sexual species and parthenogenetic strains.

The incidence of rare males in seven parthenogeneticArtemia (Crustacea: Anostraca) populations

“…The difference in the ploidy composition of samples used by different authors could be a reason for the significant variation of the rare male ratio of the same population. However, this cannot explain the higher rare male ratios observed by Qian et al (1992) and Maccari et al (2013) for the BRK and AB populations. Some unknown factors may impact the incidence of rare males in parthenogenetic Artemia.…”

“…Although the male:female ratio in cultured samples of the DF population was reported as 1:637 by Maccari et al (2013), we could not clone diploid females in this population. High variable male:female ratios have been reported for the AB population.…”

“…High variable male:female ratios have been reported for the AB population. For instance, Ren et al (1992) documented the ratio in a wild sample as 1:6086 (15 males in 91,311 specimens), Qian et al (1992) reported a ratio of 1:625 (whether from a wild or a laboratory population is unknown), and Maccari et al (2013) observed a much higher ratio of 1:116 (19 males in 2207 specimens) from cultured samples. Moreover, Qian et al (1992) documented the male:female ratio of the BRK population as 1:189.…”

“…The male:female ratio recorded for wild "parthenogenetic" populations varied from 1:6086 to 1:67 (MacDonald and Browne, 1990;Ren et al, 1992). For cultured populations, this ratio was reported to be from 1:12,499 (Gerri, Spain) (Maccari et al, 2013) to 1:11 (493 males:5595 females; recorded for a selected clone from China) (Cai, 1993). The present results show that there is significant difference among the sex ratios of the diploid Artemia from four populations with the values of male:female varying from 0.529:1000 to 1.399:1000 (Tables 2 and 3).…”

Rare diploid females coexist with rare males: a novel finding in triploid parthenogenetic populations in the psyllid Cacopsylla myrtilli (W. Wagner, 1947) (Hemiptera, Psylloidea) in northern Europe

“…However, the occurrence of rare males in some populations of obligate parthenogenetic species or lineages has been reported in various animal groups (Blackman 1972;Palmer and Norton 1990;Butlin et al 1998;Martens 1998;Rispe et al1999;Simon et al 1999;Delmotte et al 2001;Snyder et al 2006;Domes et al 2007;Engelstädter et al 2011;Maccari et al 2013). It has been questioned whether these males have any role in the evolutionary fate of asexual lineages or do they merely represent ''atavism' ' (Schön et al 2009).…”