| Mutation Description |
"Furthermore, the substitution E111G, i.e. the substitution of glutamate at residue 111 with glycine, is apparent in all of the odontocete species examined that do not possess upstream frame-shifting
mutations. Residue E111 of the SWS cone opsin corresponds to residue E113 of bovine rhodopsin, the essential Schiff’s base linkage counter-ion that stabilizes the opsin–chromophore bond (Sakmar et al. 1989; Nathans 1990)." |
10.1098/rspb.2002.2278 |
| Methodology & Validation |
"For genetic analysis, three individuals were examined from each species, except Inia geoffrensis and Platanista gangetica, where tissue availability was limited to a single individual. All procedures were performed on nuclear DNA extracted from frozen skin with lithium-chloride and chloroform (Hillis et al. 1996)." |
10.1098/rspb.2002.2278 |
| Timing of Loss |
"The distribution of these missense mutations among the species examined indicates that the loss of the SWS cone pigment type occurred relatively early in the evolution of modern cetaceans." |
10.1098/rspb.2002.2278 |
| Timing of Loss |
"Indeed, it is not possible to determine when the original loss of SWS cones occurred in cetaceans. The apparently identical 4 bp deletion present in all six mysticetes and two odontocetes (figure 3) raises the possibility that the loss of SWS cones may even have preceded the separation of the two cetacean suborders." |
10.1098/rspb.2002.2278 |
| Phenotypic |
"The absence of this visual-pigment type reduces the ability of these marine mammals to detect stimuli in the short-wave length region of the spectrum and renders them incapable of making conventional cone-based colour discriminations." |
10.1098/rspb.2002.2278 |
| Other |
"Cetaceans are the first order of mammals found to be entirely lacking one of the three ancestral photopigment types. They are also the only entire order of mammals known to lack the potential for cone-based colour vision (Jacobs 1993)." |
10.1098/rspb.2002.2278 |