CRISPR/Cas-mediated targeted mutagenesis in Daphnia magna

PLoS One. 2014 May 30;9(5):e98363. doi: 10.1371/journal.pone.0098363. eCollection 2014.


The water flea Daphnia magna has been used as an animal model in ecology, evolution, and environmental sciences. Thanks to the recent progress in Daphnia genomics, genetic information such as the draft genome sequence and expressed sequence tags (ESTs) is now available. To investigate the relationship between phenotypes and the available genetic information about Daphnia, some gene manipulation methods have been developed. However, a technique to induce targeted mutagenesis into Daphnia genome remains elusive. To overcome this problem, we focused on an emerging genome editing technique mediated by the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system to introduce genomic mutations. In this study, we targeted a functionally conserved regulator of eye development, the eyeless gene in D. magna. When we injected Cas9 mRNAs and eyeless-targeting guide RNAs into eggs, 18-47% of the survived juveniles exhibited abnormal eye morphology. After maturation, up to 8.2% of the adults produced progenies with deformed eyes, which carried mutations in the eyeless loci. These results showed that CRISPR/Cas system could introduce heritable mutations into the endogenous eyeless gene in D. magna. This is the first report of a targeted gene knockout technique in Daphnia and will be useful in uncovering Daphnia gene functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics*
  • Daphnia / genetics*
  • Eye / growth & development
  • Gene Knockout Techniques / methods
  • Genetic Engineering / methods
  • Molecular Sequence Data
  • Mutagenesis / genetics*
  • Mutation / genetics
  • Phenotype
  • RNA, Guide / genetics


  • RNA, Guide

Grant support

This study was supported by a grant from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and partially supported by the Asahi Glass Foundation. One of the authors (Y.K.) would like to acknowledge the Frontier Research Base for Global Young Researchers, Osaka University, based on the Program of MEXT, for providing financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.