Genome Study Reveals Secret Of Pacific Bluefin Tuna’s Superior Eyesight
Japanese scientists have analyzed the genome of the Pacific bluefin tuna, a highly prized fish that is also known for its superior eyesight.
AsianScientist (Jun. 20, 2013) - A team of Japanese scientists has completed the first genomic analysis of the Pacific bluefin tuna (Thunnus orientalis), providing insights into how it evolved to become an extremely efficient predator with superior vision in the ocean.
In their study, published in the Proceedings of the National Academy of Sciences, the scientists sequenced the genome of a wild-caught male Pacific bluefin tuna and compared it with other completed fish genomes.
The bluefin tuna is known the ability to spot its prey by sight and then hunt it down in the open ocean. Scientists had determined that the bluefin tuna is able to do this because it has the sharpest vision of any bony fish.
To find out which genes are responsible for vision, they first analyzed other fish genomes, where they discovered that there are five genes, known as opsins, which are involved in vision. Next, they were able to identify all five opsin genes in the Pacific bluefin tuna genome. Notably, they found that the Pacific bluefin tuna had five copies of the opsin gene responsible for green color detection. This number is the highest among all sequenced fish species.
The scientists believe that the abundance of genes responsible for green color sensitivity may be responsible for the bluefin tuna’s ability to detect its prey and other objects in the bluish ocean environment. The tuna’s superior vision may also allow it to accurately gauge the distance to its prey, making it an extremely efficient predator, they say.
Copyright: Asian Scientist Magazine; Photo: tomosuke214/Flickr.
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