The kuruma shrimp is considered an economically important species in Japan, where a large shrimp farming industry has been established, and in many countries in Asia. However, little is known about their biology and genetics despite their importance.
Researchers from Japan used two techniques to create a genetic resource of their immune-related genes that can be used for fisheries management and establishing a breeding program. The resource would hopefully uncover the kuruma shrimp's genes for immunity, growth, and reproduction.
High Numbers of Kuruma Shrimp Poses Risk for Diseases
According to the Invasive Species Compendium, the kuruma shrimp inhabits inshore waters up to 90 meters deep in the sandy mud and sandy bottoms. They are one of the largest shrimp species, which can grow between 25-30 cm ad survive low temperatures of as low as 50 degrees Fahrenheit (10 degrees Celsius).
They are considered a delicacy, and in Japan, there is a large shrimp industry established in the country. A 17 cm female kuruma shrimp can lay up to 700,000 eggs at a single spawning, which varies from March to September. However, their big population has also caused some problems because diseases spread quickly among them.
According to Phys.org, one of the concerning diseases of the kuruma shrimp is the white spot disease. It is one of the most threatening pathogens to shrimp aquaculture that is highly lethal and contagious, wherein outbreaks could wipe out an entire shrimp farm in just a few days.
Researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) and Tokyo University of Marine Science and Technology established a useful genetic resource on the kuruma shrimp's immune-related genes to produce disease-resistant shrimps or vaccines against the deadly shrimp disease.
The Making of Kuruma Shrimp Genetic Resource
In their study, titled "Genome and Transcriptome Assemblies of the Kuruma Shrimp, Marsupenaeus japonicus," published in G3: Genes l Genomes l Genetics, researchers used genome sequencing and transcriptome sequencing to generate the genetic resource of the kuruma shrimp.
According to the news release via Mirage News, a genome is a full set of genetic information subdivided into genes that make up the DNA base pairs and contain instructions to make protein. Meanwhile, a transcriptome is a collection of gene readouts and is sometimes considered a reflection of the genome. Some genes could be related to immunity, and some may contain variations related to stronger disease resistance, which need to be identified to establish a line of disease-resistant shrimp.
The team first deciphered the genome of the kuruma shrimp taken from a commercial farm in Okinawa and then generated initial genome sequences. The process produced many short DNA sequences that were useful but did not provide enough clues for the team. Then, they used transcriptome sequencing to produce longer, less precise DNA sequences. Combining the two techniques gave them a draft of the genome.
Then the team analyzed 49 RNA samples of different shrimps from larvae to adults, wherein they could produce a total of 66,406 high-quality gene drafts of the transcriptome.
Researchers emphasized that the kuruma shrimp provided a comprehensive catalog of immune-related genes that will help scientists better understand how shrimps respond to diseases, develop strategies to prevent outbreaks, and address some aspects of shrimp biology, particularly its growth and reproduction.
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