English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  Sexual reproduction involving the fusion of egg and sperm is prevailing among eukaryotes. In contrast, the nematode  Diploscapter coronatus , a close relative of the model  Caenorhabditis elegans , reproduces parthenogenetically. Neither males nor sperm have been observed and some steps of meiosis are apparently skipped in this species. To uncover the genomic changes associated with the evolution of parthenogenesis in this nematode, we carried out a genome analysis.    Results  We obtained a 170 Mbp draft genome in only 511 scaffolds with a N 50  length of 1 Mbp. Nearly 90% of these scaffolds constitute homologous pairs with a 5.7% heterozygosity on average and inversions and translocations, meaning that the 170 Mbp sequences correspond to the diploid genome. Fluorescent staining shows that the  D. coronatus  genome consists of two chromosomes (2n = 2). In our genome annotation, we found orthologs of 59% of the  C. elegans  genes. However, a number of genes were missing or very divergent. These include genes involved in sex determination (e.g.  xol-1 ,  tra- 2) and meiosis (e.g. the kleisins  rec-8  and  coh-3/4 ) giving a possible explanation for the absence of males and the second meiotic division. The high degree of heterozygosity allowed us to analyze the expression level of individual alleles. Most of the homologous pairs show very similar expression levels but others exhibit a 2–5-fold difference.    Conclusions  Our high-quality draft genome of  D. coronatus  reveals the peculiarities of the genome of parthenogenesis and provides some clues to the genetic basis for parthenogenetic reproduction. This draft genome should be the basis to elucidate fundamental questions related to parthenogenesis such as its origin and mechanisms through comparative analyses with other nematodes. Furthermore, being the closest outgroup to the genus  Caenorhabditis , the draft genome will help to disclose many idiosyncrasies of the model  C. elegans  and its congeners in future studies.    Electronic supplementary material  The online version of this article (doi:10.1186/s12864-017-3860-x) contains supplementary material, which is available to authorized users.

Genome analysis of Diploscapter coronatus: insights into molecular peculiarities of a nematode with parthenogenetic reproduction