Evolutionary Changes Of The Importance Of Olfaction In Cetaceans Based On The Olfactory Marker Protein Gene
Aquatic adaptation; deletion causes; Echolocation; Eocene whale; Filter-feeder; Genetics & Heredity; india; marine mammals; neurons; nucleotide; OMP; sea; sequences; whales
Odontocetes and mysticetes are two extant suborders of cetaceans. It is reported that the former have no sense of olfaction, while the latter can smell in air. To explain the ecological reason why mysticetes still retain their sense of smell, two hypotheses have been proposed - the echolocation-priority hypothesis, which assumes that the acquisition of echolocation causes the reduction of the importance of olfaction, and the filter-feeder hypothesis, which assumes that olfactory ability is important for filter-feeders to locate their prey because clouds of plankton give off a peculiar odor. The olfactory marker protein (OMP) is almost exclusively expressed in vertebrate olfactory receptor neurons, and is considered to play important roles in olfactory systems. In this study, full-length open reading frames of OMP genes were identified in 6 cetacean species and we analyzed the nonsynonymous to synonymous substitution rate ratio based on the maximum likelihood method. The evolutionary changes of the selective pressures on OMP genes did fit better to the filter-feeder hypothesis than to the echolocation-priority hypothesis. In addition, no pseudogenization mutations are found in all five odontocetes OMP genes investigated in this study. It may suggest that OMP retains some function even in 'anosmic' odontocetes. (C) 2011 Elsevier B.V. All rights reserved.
Kishida T; Thewissen J G M
Gene
2012
2012-01
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/j.gene.2011.11.013" target="_blank" rel="noreferrer noopener">10.1016/j.gene.2011.11.013</a>
Histomorphometry of the embryonic avian growth plate by proton nuclear magnetic resonance microscopy
appearance; articular-cartilage; bone-formation; cartilage; chick; deposits; diffusion; Endocrinology & Metabolism; growth-plate; hyaline cartilage; mineral; morphology; mr-imaging characteristics; nuclear magnetic resonance microscopy; relaxation; sequences
Quantitative nuclear magnetic resonance (NMR) microscopy was used to characterize the biochemical and morphological properties of the different zones within the growth plate of an embryonic chick femur. For precalcified tissue, water proton transverse relaxation times (T-2) and magnetization transfer values (MT) were directly and inversely dependent, respectively, on tissue cellularity, defined as the intracellular area per unit area on histological sections. T-2 values extrapolated for intra- and extracellular water were 96 ms and 46 ms, respectively. The extracellular T-2 was comparable with that measured for mature cartilage. The MT values extrapolated for intra- and extracellular compartments were 0.32 and 0.85, respectively, These values were comparable with those values reported in the literature for cell pellets and for mature cartilage tissue. Thus, cellularity dominated the NMR properties of this immature cartilage tissue. Mineral deposits within calcified cartilage and periosteal bone invoked NMR relaxation processes that were dependent on the inorganic mineral phase; Additionally, collagen molecules present in mineralized zones gave rise to a significant MT effect. These results show the utility of water proton NMR microscopy for assessing both the organic and inorganic ph ases within mineralized tissues.
Potter K; Landis W J; Spencer R G S
Journal of Bone and Mineral Research
2001
2001-06
Journal Article
<a href="http://doi.org/10.1359/jbmr.2001.16.6.1092" target="_blank" rel="noreferrer noopener">10.1359/jbmr.2001.16.6.1092</a>