Transparent squid. This is the creation of scientists from the Marina Biology Laboratory (MBL), who for the first time have achieved the elimination of genes in a cephalopod, which can lead to applications not only in biology, but also in robotics or artificial intelligence. The team, which has just published its results in « Current Biology», Used the genome editing tool CRISPR-Cas9 to suppress a pigmentation gene in squid embryos, which removed pigmentation in the eyes and skin cells (chromatophores) with high efficiency.
“This is a critical first step towards the ability to remove and knock out genes in cephalopods to address a number of biological questions,” he states in a release Joshua Rosenthal, principal scientist of the MBL and main author of the work.
The cephalopods (squid, octopus and cuttlefish) have the largest brain of all invertebrates, an extended nervous system capable of causing instant camouflage and the ability to broadly recode your own genetic information into messenger RNA. These animals open many avenues for study and have applications in a wide range of fields, from evolution and development, to medicine, robotics, materials science, and artificial intelligence.
The ability to remove a gene to test its function is an important step in the development of cephalopods as genetically treatable organisms for biological research, increasing the number of species that currently dominate genetic studies, such as fruit flies, zebrafish and mice. It is also a necessary step to have the ability to generate genes that facilitate research, such as those that encode fluorescent proteins that can be imaged to track neuronal activity or other dynamic processes.
«CRISPR-Cas9 worked very well in the Doryteuthis; It was surprisingly efficient, “says Rosenthal. Much more challenging was delivering the CRISPR-Cas system to the single-celled squid embryo, which is surrounded by an extremely resistant outer shell, and then raising the embryo through hatching. The team developed micro-scissors to trim the surface of the egg and a beveled quartz needle to then use the CRISPR-Cas9 reagents.
A Nobel animal
Studies with Doryteuthis pealeii have led to fundamental advances in neurobiology, beginning with the description of action potential (nerve impulse) in the 1950s, a discovery by which Alan Hodgkin and Andrew Huxleand they became Nobel Prize winners in 1963.
Rosenthal and his colleagues recently discovered extensive recoding of MRNA in the nervous system of Doryteuthis and other cephalopods. This research is in development for possible biomedical applications, such as pain control therapy.
However, D. pealeii is not an ideal species to develop as a genetic research organism. It is large and takes up a lot of space in the tank and, most importantly, no one has been able to grow it through multiple generations in the laboratory. For these reasons, the next goal of the MBL Cephalopod program is to transfer the new removal technology to a smaller cephalopod species, Euprymna berryi (hummingbird squid), which is relatively easy to grow to produce genetic strains.
The MBL Cephalopod Program is part of the MBL New Research Organisms Initiative, which is expanding the palette of genetically manageable organisms available for research, and thus expanding the universe of biological questions that can be asked.