idw – Informationsdienst Wissenschaft

Nachrichten, Termine, Experten

Grafik: idw-Logo
idw-Abo
Medienpartner:
Wissenschaftsjahr


Share on: 
05/09/2019 20:00

New type of highly sensitive vision discovered in deep-sea fish

Reto Caluori Kommunikation & Marketing
Universität Basel

    The deep sea is home to fish species that can detect various wavelengths of light in near-total darkness. Unlike other vertebrates, they have several genes for the light-sensitive photopigment rhodopsin, which likely enables these fish to detect bioluminescent signals from light-emitting organs. The findings were published in the journal Science by an international team of researchers led by evolutionary biologists from the University of Basel.

    Color vision in vertebrates is usually achieved through the interaction of various photopigments in the cone cells found in the retina. Each of these photopigments reacts to a certain wavelength of light. In humans, for example, these wavelengths are the red, green and blue range of the light spectrum. Color vision is only possible in daylight, however. In darkness, vertebrates detect the few available light particles with their light-sensitive rod cells, which contain only a single type of the photopigment rhodopsin – explaining why nearly all vertebrates are color-blind at night.

    A genetic record for the silver spinyfin

    An international team of researchers lead by Professor Walter Salzburger from the University of Basel recently analyzed more than 100 fish genomes, including those of fish living in deep-sea habitats. The zoologists discovered that certain deep-sea fish have expanded their repertoire of rhodopsin genes. In the case of the silver spinyfin (Diretmus argenteus), they found no less than 38 copies of the rhodopsin gene, in addition to two other opsins of a different type. “This makes the darkness-dwelling silver spinyfin the vertebrate with the most photopigment genes by far,” explains Salzburger.

    The deep-sea fish’s many different rhodopsin gene copies have each adapted to detect a certain wavelength of light, the researchers further reported. They demonstrated this through computer simulations and functional experiments on rhodopsin proteins regenerated in the lab. The genes cover exactly the wavelength range of light “produced” by light-emitting organs of deep-sea organisms. This is known as bioluminescence, which is the ability of an organism to produce light on its own or with the help of other organisms. For example, anglerfish attract prey with their bioluminescent organs.

    Detecting signals in the dark

    The deep sea is the largest habitat on Earth and yet one of the least explored due to its inaccessibility. Many organisms have adapted to life in the near-total darkness of this inhospitable environment. For example, many fish have developed highly sensitive telescope eyes that allow them to detect the tiny amount of residual light that makes it to the depths of the ocean.

    In vertebrates, 27 key spectral tuning sites have been identified in the protein for rhodopsin. These sites directly affect which wavelengths are detected. The researchers discovered that in the various gene copies of the deep-sea silver spinyfin, 24 of these positions exhibited mutations.

    “It appears that deep-sea fish have developed this multiple rhodopsin-based vision several times independently of each other, and that this is specifically used to detect bioluminescent signals,” says Salzburger. He adds that this may give deep-sea fish an evolutionary advantage by allowing them to much better see potential prey or predators.

    “In any case, our findings help redefine the current paradigm of vertebrate vision in terms of the role of rod photoreceptors,” the zoologists write. This presents yet another instance in which analyzing whole genomes led to new biological discoveries.


    Contact for scientific information:

    Prof. Dr. Walter Salzburger, University of Basel, Department of Environmental Sciences, Zoology, Tel. +41 61 207 03 03, Email: walter.salzburger@unibas.ch


    Original publication:

    Zuzana Musilova, Fabio Cortesi, Michael Matschiner, Wayne I. L. Davies, Jagdish Suresh Patel, Sara M. Stieb, Fanny de Busserolles, Martin Malmstrøm, Ole K. Tørresen, Celeste J. Brown, Jessica K. Mountford, Reinhold Hanel, Deborah L. Stenkamp, Kjetill S. Jakobsen, Karen L. Carleton, Sissel Jentoft, Justin Marshall, Walter Salzburger
    Vision using multiple distinct rod opsins in deep-sea fishes
    Science (2019), doi: 10.1126/science.aav4632
    https://science.sciencemag.org/lookup/doi/10.1126/science.aav4632


    Criteria of this press release:
    Journalists, Scientists and scholars, all interested persons
    Biology, Zoology / agricultural and forest sciences
    transregional, national
    Research results, Scientific Publications
    English


    The lanternfish has bioluminescent organs and an increased number of rhodopsin genes.


    For download

    x

    The silver spinyfin (Diretmus argenteus) is the vertebrate with the highest number of opsin genes.


    For download

    x

    Help

    Search / advanced search of the idw archives
    Combination of search terms

    You can combine search terms with and, or and/or not, e.g. Philo not logy.

    Brackets

    You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).

    Phrases

    Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.

    Selection criteria

    You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).

    If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).

    Cookies optimize the use of our services. By surfing on idw-online.de you agree to the use of cookies. Data Confidentiality Statement
    Okay