Cone visual pigments of aquatic mammals

2005 ◽  
Vol 22 (6) ◽  
pp. 873-879 ◽  
Author(s):  
LUCY A. NEWMAN ◽  
PHYLLIS R. ROBINSON

It has long been hypothesized that the visual systems of animals are evolutionarily adapted to their visual environment. The entrance many millions of years ago of mammals into the sea gave these new aquatic mammals completely novel visual surroundings with respect to light availability and predominant wavelengths. This study examines the cone opsins of marine mammals, hypothesizing, based on previous studies [Fasick et al. (1998) and Levenson & Dizon (2003)], that the deep-dwelling marine mammals would not have color vision because the pressure to maintain color vision in the dark monochromatic ocean environment has been relaxed. Short-wavelength-sensitive (SWS) and long-wavelength-sensitive (LWS) cone opsin genes from two orders (Cetacea and Sirenia) and an additional suborder (Pinnipedia) of aquatic mammals were amplified from genomic DNA (for SWS) and cDNA (for LWS) by PCR, cloned, and sequenced. All animals studied from the order Cetacea have SWS pseudogenes, whereas a representative from the order Sirenia has an intact SWS gene, for which the corresponding mRNA was found in the retina. One of the pinnipeds studied (harp seal) has an SWS pseudogene, while another species (harbor seal) appeared to have an intact SWS gene. However, no SWS cone opsin mRNA was found in the harbor seal retina, suggesting a promoter or splice site mutation preventing transcription of the gene. The LWS opsins from the different species were expressed in mammalian cells and reconstituted with the 11-cis-retinal chromophore in order to determine maximal absorption wavelengths (λmax) for each. The deeper dwelling Cetacean species had blue shifted λmax values compared to shallower-dwelling aquatic species. Taken together, these findings support the hypothesis that in the monochromatic oceanic habitat, the pressure to maintain color vision has been relaxed and mutations are retained in the SWS genes, resulting in pseudogenes. Additionally, LWS opsins are retained in the retina and, in deeper-dwelling animals, are blue shifted in λmax.

2019 ◽  
Vol 37 (3) ◽  
pp. 811-827 ◽  
Author(s):  
Nathan S Hart ◽  
Trevor D Lamb ◽  
Hardip R Patel ◽  
Aaron Chuah ◽  
Riccardo C Natoli ◽  
...  

Abstract The diversity of color vision systems found in extant vertebrates suggests that different evolutionary selection pressures have driven specializations in photoreceptor complement and visual pigment spectral tuning appropriate for an animal’s behavior, habitat, and life history. Aquatic vertebrates in particular show high variability in chromatic vision and have become important models for understanding the role of color vision in prey detection, predator avoidance, and social interactions. In this study, we examined the capacity for chromatic vision in elasmobranch fishes, a group that have received relatively little attention to date. We used microspectrophotometry to measure the spectral absorbance of the visual pigments in the outer segments of individual photoreceptors from several ray and shark species, and we sequenced the opsin mRNAs obtained from the retinas of the same species, as well as from additional elasmobranch species. We reveal the phylogenetically widespread occurrence of dichromatic color vision in rays based on two cone opsins, RH2 and LWS. We also confirm that all shark species studied to date appear to be cone monochromats but report that in different species the single cone opsin may be of either the LWS or the RH2 class. From this, we infer that cone monochromacy in sharks has evolved independently on multiple occasions. Together with earlier discoveries in secondarily aquatic marine mammals, this suggests that cone-based color vision may be of little use for large marine predators, such as sharks, pinnipeds, and cetaceans.


2017 ◽  
Vol 48 (S 01) ◽  
pp. S1-S45
Author(s):  
O. Schwartz ◽  
J. Althaus ◽  
B. Fiedler ◽  
K. Heß ◽  
W. Paulus ◽  
...  

2018 ◽  
Vol 70 (5) ◽  
Author(s):  
Melahat M. Oguz ◽  
Meltem Akcaboy ◽  
Asuman Gurkan ◽  
Esma Altinel Acoglu ◽  
Pelin Zorlu ◽  
...  

2020 ◽  
Vol 15 (3) ◽  
pp. 211-235
Author(s):  
Josephine Chazot ◽  
Ludovic Hoarau ◽  
Pamela Carzon ◽  
Jeanne Wagner ◽  
Stéphanie Sorby ◽  
...  

Whale-watching activities provide important socioeconomic benefits for local communities and constitute powerful platform incentives for marine mammals' protection or more broadly marine environments. However, these activities can cause adverse effects on targeted populations, with considerable downside associated risks of injuries and fatality for whale watchers during inwater interactions. France with its overseas territories has the second largest exclusive economic zone (EEZ), in which more than half of existing cetacean species are encountered. In these territories, recreational and commercial whale watching, including swim-with cetacean activities, have recently developed. Yet few studies focused on these activities and their associated impacts across French territories, leading to an unclear assessment of the situation. To address this issue, we reviewed cetaceans' occurrence within the French EEZ, whale-watching industry, targeted species, local management of marine mammal-based tourism activities, and regulations in France mainland and some overseas territories (Reunion Island, Mayotte, and French Polynesia). Fortyeight species are encountered in the French EEZ, and 15 are targeted by whale-watching activities. A total of 185 operators, including 34% offering swim-with-cetaceans tours, offered trips in France and overseas in 2019. While several more or less restrictive regulations exist locally, our results indicate that French's national legal framework for marine mammals' protection remains inadequate and insufficient to cope with the recent development of this activity. As conservation biologists, managers, and stakeholders from these French territories, we cooperated to provide general guidelines for a sustainable development of whale watching at a national scale. We urge (1) to legally acknowledge and regulate whale-watching commercial activities; (2) to create a national legal framework regarding whale watching and swim-with marine mammals practices, while accounting for local distinctiveness and disparities across regions; (3) to conduct more research to evaluate local short- and long-term impacts on targeted marine mammal populations as well as the socioeconomic benefits; and (4) to reinforce synergetic relations between the different stakeholders.


2015 ◽  
Vol 8 ◽  
Author(s):  
A. Mel Cosentino

Orcinus orcais a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items. Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes®binoculars (25×, 80 mm). The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel. On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is the first predatory event reported in the literature.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yash Sondhi ◽  
Emily A. Ellis ◽  
Seth M. Bybee ◽  
Jamie C. Theobald ◽  
Akito Y. Kawahara

AbstractOpsins, combined with a chromophore, are the primary light-sensing molecules in animals and are crucial for color vision. Throughout animal evolution, duplications and losses of opsin proteins are common, but it is unclear what is driving these gains and losses. Light availability is implicated, and dim environments are often associated with low opsin diversity and loss. Correlations between high opsin diversity and bright environments, however, are tenuous. To test if increased light availability is associated with opsin diversification, we examined diel niche and identified opsins using transcriptomes and genomes of 175 butterflies and moths (Lepidoptera). We found 14 independent opsin duplications associated with bright environments. Estimating their rates of evolution revealed that opsins from diurnal taxa evolve faster—at least 13 amino acids were identified with higher dN/dS rates, with a subset close enough to the chromophore to tune the opsin. These results demonstrate that high light availability increases opsin diversity and evolution rate in Lepidoptera.


2021 ◽  
Vol 22 (7) ◽  
pp. 3786
Author(s):  
Andreas Brodehl ◽  
Alexey Meshkov ◽  
Roman Myasnikov ◽  
Anna Kiseleva ◽  
Olga Kulikova ◽  
...  

About 50% of patients with arrhythmogenic cardiomyopathy (ACM) carry a pathogenic or likely pathogenic mutation in the desmosomal genes. However, there is a significant number of patients without positive familial anamnesis. Therefore, the molecular reasons for ACM in these patients are frequently unknown and a genetic contribution might be underestimated. Here, we used a next-generation sequencing (NGS) approach and in addition single nucleotide polymor-phism (SNP) arrays for the genetic analysis of two independent index patients without familial medical history. Of note, this genetic strategy revealed a homozygous splice site mutation (DSG2–c.378+1G>T) in the first patient and a nonsense mutation (DSG2–p.L772X) in combination with a large deletion in DSG2 in the second one. In conclusion, a recessive inheritance pattern is likely for both cases, which might contribute to the hidden medical history in both families. This is the first report about these novel loss-of-function mutations in DSG2 that have not been previously identi-fied. Therefore, we suggest performing deep genetic analyses using NGS in combination with SNP arrays also for ACM index patients without obvious familial medical history. In the future, this finding might has relevance for the genetic counseling of similar cases.


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