Scientists Decode The Asian Catfish Genome

Researchers in Japan and Vietnam have sequenced the genome of the Asian catfish, which could help fisheries identify important genes for rapid growth and disease resistance.

AsianScientist (Oct. 30, 2018) – In a study published in the journal BMC Genomics, scientists in Japan and Vietnam have sequenced the genome of the striped catfish Pangasianodon hypophthalmus.

P. hypophthalmus is found in the Mekong River, the longest river in Southeast Asia and the largest inland fishery in the world. Vietnam stands as the leading producer of the species, culturing an estimated 1.1 million tons of the fish in a single year. But unlike other commercial fish, such as the Atlantic cod or channel catfish, little genomic data exists to guide striped catfish aquaculture.

In this study, scientists at the Okinawa Institute of Science and Technology Graduate University (OIST), Japan, teamed up with researchers at the Vietnam Academy of Science and Technology to decode the striped catfish’s entire genome. Using next-generation sequencing techniques, the researchers gathered high-quality genomic data and assembled it into a complete genome.

They compared the new genome to previously published genomic data from channel catfish and zebrafish—a model organism that is evolutionarily related to catfish. The scientists found distinct differences between the Asian catfish and its American cousin, also highlighting differences between the Asian catfish and the zebrafish.

In particular, they identified the loss of two genes in the Asian catfish that remain intact in the zebrafish. These genes are involved in the production of natural sunscreen in fishes. Because catfish feed at the bottom of rivers, beyond the reach of UV-rays, they likely do not require sunscreen, hence the genes were eventually lost from the catfish genome. The scientists also reported that the striped catfish has more insulin-like growth factor genes than zebrafish, which may be key to its healthy growth and development.

The researchers also assembled a genome map that paves the way for future research comparing catfish species, tracing their lineages and investigating their gene function. Evolutionary biologists and aquaculturists both stand to learn from the striped catfish genome, now that it has been decoded.

In the immediate future, aquaculturists can begin to seek out and select for optimal DNA fragments, known as molecular markers, in their own striped catfish, said Professor Kim Oanh T. P., a laboratory leader at the Institute of Genome Research at the Vietnam Academy of Science and Technology, who is a co-first author of the study.

“With this genomic data, it will be easy to check the diversification present in individual catfish populations,” said Dr. Eiichi Shoguchi, group leader of the Marine Genomics Unit at OIST and a co-first author of the study. “In aquaculture, for example, an individual fish may be more resilient against disease than another. Now, you can check that individual’s genome and learn which gene is related to disease resistance.”

The article can be found at: Kim et al. (2018) A Draft Genome of the Striped Catfish, Pangasianodon hypophthalmus, for Comparative Analysis of Genes Relevant to Development and a Resource for Aquaculture Improvement.


Source: Okinawa Institute of Science and Technology Graduate University; Photo: Pixabay.
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