To study the fundamentals of biology, scientists have traditionally turned to a group of organisms, such as fruit flies, zebrafish, and mice, among others. All of them have a short life, a small body, can be raised for several generations in the laboratory and have been developed in genetic research. However, these organisms leave out a whole swath of biological diversity .
Now, in a study published in the journal Frontiers in Marine Science , researchers from the Marine Biological Laboratory ( MBL ) present the culture methods of a species with suitable characteristics to be a good animal model in biological research. They are Octopus chierchia , the pygmy zebra octopus .
“The pygmy zebra octopus has certain biological characteristics that make it attractive and more appropriate for laboratory research, compared to other octopuses,” says Bret Grasse , MBL researcher and co-author from the article.
Also known as the lesser Pacific striped octopus, O. chierchiae , it shares many useful similarities with other research organisms, such as its small size, but also has unique characteristics that distinguish it from others cephalopods – the group of animals that includes octopuses, squid and cuttlefish.
Its small size, sexual dimorphism, and predictable reproduction make the pygmy zebra octopus an ideal candidate for laboratory research
One of them is that most octopuses live fast and die young. “They reproduce once and immediately begin to age and then die relatively quickly,” notes Anik Grearson , a co-author of the paper. However, and unlike other species of octopus, a female of this species lays several clutches of 30 to 90 eggs throughout her reproductive period.
“We can mate them and know exactly when they are going to lay their eggs. We also know how long they will incubate and we can rear the larvae with a relatively high survival rate compared to other octopuses ”, explains the expert.
Its small size, sexual dimorphism and predictable reproduction make this species an ideal candidate for further exploration and investigation, according to the study authors.
Ideal candidate for research
The MBL cephalopod mariculture team successfully raised the pygmy octopus in the laboratory through multiple generations in 2019 , which was a milestone worldwide. Rearing multiple generations in the laboratory is known as end of life cycle and is essential in research, as it allows scientists to study the function of genes and the effects of mutations from one generation to another.
The possibility of successfully raising octopuses in a laboratory opens “a novel science that has not been possible until now,” Grasse emphasizes.
Multiple generation rearing in the laboratory is known as life cycle closure and allows the study of gene function and mutations from one generation to the next
Scientists around the world study cephalopods to understand things from camouflage and limb dexterity to regeneration and neurobiology .
In the United States, most researchers studying these organisms use the California two-spotted octopus ( O. bimaculoides ). However, this species has not yet been successfully bred in the laboratory, so its study animals are captured in the wild and sent to different laboratories from California.
Furthermore, another problem is that these cephalopods are territorial and therefore each organism must be housed individually. An adult two-spotted octopus is the size of a baseball, while an adult pygmy zebra octopus is the size of a grape . This makes the small species more suitable, especially in laboratories with little space.
“Now we have this species of octopus that is really small and can be raised regularly,” concludes Grearson.
Reference:
Grearson et al. “The Lesser Pacific Striped Octopus, Octopus chierchiae : An Emerging Laboratory Model”. Frontiers in Marine Science 2021
Rights: Creative Commons.