gene knockout approaches, scientists can target specific regions of DNA using techniques like CRISPR/Cas9 to understand the function of certain genes based on the absence of the gene of interest. For example, gene knockouts of the Sox2 gene confirm this region’s role in neural stem cell amplification in the axolotl. The technology to do more complex conditional gene knockouts, or conditional knockouts that give the scientist spatiotemporal control of the gene is not yet suitable for axolotls. However, research in this field continues to develop and is made easier by recent sequencing of the genome and resources created for scientists, including data portals that contain axolotl genome and transcriptome reference assemblies to identify orthologs. Nematodes The nematode Caenorhabditis elegans is one of the major model organisms for researching molecular biology. RNA interference (RNAi) was discovered in C elegans and could be induced by simply feeding them bacteria modified to express double stranded RNA. It is also relatively easy to produce stable transgenic nematodes and this along with RNAi are the major tools used in studying their genes. The most common use of transgenic nematodes has been studying gene expression and localisation by attaching reporter genes. Transgenes can also be combined with RNAi to rescue phenotypes, altered to study gene function, imaged in real time as the cells develop or used to control expression for different tissues or developmental stages. Transgenic nematodes have been used to study viruses, toxicology, and diseases and to detect environmental pollutants. Other Systems have been developed to create transgenic organisms in a wide variety of other animals. The gene responsible for albinism in sea cucumbers has been found, and used to engineer white sea cucumbers, a rare delicacy. The technology also opens the way to investigate the genes responsible for some of the cucumbers more unusual traits, including hibernating in summer, eviscerating their intestines, and dissolving their bodies upon death. Flatworms have the ability to regenerate themselves from a single cell. Until 2017 there was no effective way to transform them, which hampered research. By using microinjection and radiation, scientists have now created the first genetically modified flatworms. The bristle worm, a marine annelid, has been modified. It is of interest due to its reproductive cycle being synchronized with lunar phases, regeneration capacity and slow evolution rate. Cnidaria such as Hydra and the sea anemone Nematostella vectensis are attractive model organisms to study the evolution of