Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia.

Marta Maccari,Francisco Hontoria,Francisco Amat,Africa Gómez

doi:10.7717/peerj.439

Abstract

Contagious parthenogenesis—a process involving rare functional males produced by a parthenogenetic lineage which mate with coexisting sexual females resulting in fertile parthenogenetic offspring—is one of the most striking mechanisms responsible for the generation of new parthenogenetic lineages. Populations of the parthenogenetic diploid brine shrimp Artemia produce fully functional males in low proportions. The evolutionary role of these so-called Artemia rare males is, however, unknown. Here we investigate whether new parthenogenetic clones could be obtained in the laboratory by mating these rare males with sexual females. We assessed the survival and sex ratio of the hybrid ovoviviparous offspring from previous crosses between rare males and females from all Asiatic sexual species, carried out cross-mating experiments between F1 hybrid individuals to assess their fertility, and estimated the viability and the reproductive mode of the resulting F2 offspring. Molecular analysis confirmed the parentage of hybrid parthenogenetic F2. Our study documents the first laboratory synthesis of new parthenogenetic lineages in Artemia and supports a model for the contagious spread of parthenogenesis. Our results suggest recessive inheritance but further experiments are required to confirm the likelihood of the contagious parthenogenesis model.

Highlights

Parthenogenesis in animals has evolved through different molecular mechanisms that influence the initial genetic variability of parthenogenetic strains and have important implications on their evolutionary success and persistence (Simon et al, 2003)
We assess the reproductive role of rare males and investigate whether new parthenogenetic clones could be produced in the laboratory as support for the contagious origin of parthenogenetic lineages in Artemia. For this purpose, (1) we assess the survival and sex ratio of the hybrid ovoviviparous offspring obtained from the previous crosses from Maccari et al (2013) between rare males and four Asiatic sexual species, (2) we carry out cross-mating experiments between these F1 hybrid individuals to assess their fertility, (3) we estimate the viability and the reproductive mode of the resulting F2 offspring; (4) we demonstrate genetically that parthenogenetic F2 are the descendants of the original crosses
This study shows that Artemia has the potential of generating parthenogenetic strains through contagious parthenogenesis

Summary

Introduction

Parthenogenesis in animals has evolved through different molecular mechanisms that influence the initial genetic variability of parthenogenetic strains and have important implications on their evolutionary success and persistence (Simon et al, 2003). One of the most striking mechanisms responsible for the generation of new parthenogenetic lineages is contagious parthenogenesis (Simon et al, 2003; Schon, Martens & van Dijk, 2009) This involves a parthenogenetic lineage able to produce functional males, which mate with coexisting sexual females producing fertile parthenogenetic hybrid offspring. In North American D. pulex parthenogenetic lineages, at least two distinct unrecombined haplotypes on chromosome VIII and IX are implied in the sex-limited meiosis suppression (Lynch et al, 2008; Eads et al, 2012; Tucker et al, 2013) These haplotypes leading to obligate parthenogenesis in D. pulex stem from a single recent event of hybridization with its sister taxon D. pulicaria (Xu et al, 2013; Tucker et al, 2013). Multiple new parthenogenetic lineages have arisen since this event as males produced by asexual lineages spread these parthenogenesis-inducing haplotypes by mating with sexual females

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