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Citation for Study 20521

Citation title: "Inactivation of the Olfactory Marker Protein (OMP) Gene in River Dolphins and other Odontocete Cetaceans".

Study name: "Inactivation of the Olfactory Marker Protein (OMP) Gene in River Dolphins and other Odontocete Cetaceans".

This study is part of submission 20521 (Status: Published).

Citation

Springer M.S., & Gatesy J. 2017. Inactivation of the Olfactory Marker Protein (OMP) Gene in River Dolphins and other Odontocete Cetaceans. Molecular Phylogenetics and Evolution, .

Authors

• Springer M.S.
• Gatesy J.

Abstract

Various toothed whales (Odontoceti) are unique among mammals in lacking olfactory bulbs as adults and are thought to be anosmic (lacking the olfactory sense). At the molecular level, toothed whales have high percentages of pseudogenic olfactory receptor genes, but species that have been investigated to date retain an intact copy of the olfactory marker protein gene (OMP), which is highly expressed in olfactory receptor neurons and may regulate the temporal resolution of olfactory responses. One hypothesis for the retention of intact OMP in diverse odontocete lineages is that this gene is pleiotropic with additional functions that are unrelated to olfaction. Recent expression studies provide some support for this hypothesis. Here, we report OMP sequences for representatives of all extant cetacean families and provide the first molecular evidence for inactivation of this gene in vertebrates. Specifically, OMP exhibits independent inactivating mutations in six different odontocete lineages: four river dolphin genera (Platanista, Lipotes, Pontoporia, Inia), sperm whale (Physeter), and harbor porpoise (Phocoena). These results suggest that the only essential role of OMP that is maintained by natural selection is in olfaction, although a non-olfactory role for OMP cannot be ruled out for lineages that retain an intact copy of this gene. Available genome sequences from cetaceans and close outgroups provide evidence of inactivating mutations in two additional genes (CNGA2, CNGA4), which imply further pseudogenization events in the olfactory cascade of odontocetes. Selection analyses demonstrate that evolutionary constraints on all three genes (OMP, CNGA2, CNGA4) have been greatly reduced in Odontoceti, but retain a signature of purifying selection on the stem Cetacea branch and in Mysticeti (baleen whales). This pattern is compatible with the ?echolocation-priority? hypothesis for the evolution of OMP, which posits that negative selection was maintained in the common ancestor of Cetacea and was not relaxed significantly until the evolution of echolocation in Odontoceti.

Keywords

anosmia, Cetacea, echolocation, Odontoceti, olfaction, olfactory marker protein

External links

About this resource

• Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S20521
• Other versions: Nexus NeXML
• Show BibTeX reference

  		@ARTICLE{TreeBASE2Ref26825,
  	 author = {Mark S Springer and John  Gatesy},
  	 title = {Inactivation of the Olfactory Marker Protein (OMP) Gene in River Dolphins and other Odontocete Cetaceans},
  	 year = {2017},
  	 keywords = {anosmia, Cetacea, echolocation, Odontoceti, olfaction, olfactory marker protein},
  	 doi = {},
  	 url = {http://},
  	 pmid = {},
  	 journal = {Molecular Phylogenetics and Evolution},
  	 volume = {},
  	 number = {},
  	 pages = {},
  	 abstract = {Various toothed whales (Odontoceti) are unique among mammals in lacking olfactory bulbs as adults and are thought to be anosmic (lacking the olfactory sense). At the molecular level, toothed whales have high percentages of pseudogenic olfactory receptor genes, but species that have been investigated to date retain an intact copy of the olfactory marker protein gene (OMP), which is highly expressed in olfactory receptor neurons and may regulate the temporal resolution of olfactory responses. One hypothesis for the retention of intact OMP in diverse odontocete lineages is that this gene is pleiotropic with additional functions that are unrelated to olfaction. Recent expression studies provide some support for this hypothesis. Here, we report OMP sequences for representatives of all extant cetacean families and provide the first molecular evidence for inactivation of this gene in vertebrates. Specifically, OMP exhibits independent inactivating mutations in six different odontocete lineages: four river dolphin genera (Platanista, Lipotes, Pontoporia, Inia), sperm whale (Physeter), and harbor porpoise (Phocoena). These results suggest that the only essential role of OMP that is maintained by natural selection is in olfaction, although a non-olfactory role for OMP cannot be ruled out for lineages that retain an intact copy of this gene. Available genome sequences from cetaceans and close outgroups provide evidence of inactivating mutations in two additional genes (CNGA2, CNGA4), which imply further pseudogenization events in the olfactory cascade of odontocetes. Selection analyses demonstrate that evolutionary constraints on all three genes (OMP, CNGA2, CNGA4) have been greatly reduced in Odontoceti, but retain a signature of purifying selection on the stem Cetacea branch and in Mysticeti (baleen whales). This pattern is compatible with the ?echolocation-priority? hypothesis for the evolution of OMP, which posits that negative selection was maintained in the common ancestor of Cetacea and was not relaxed significantly until the evolution of echolocation in Odontoceti. }
  }
  		

• Show RIS reference

  		TY  - JOUR
  ID  - 26825
  AU  - Springer,Mark S
  AU  - Gatesy,John 
  T1  - Inactivation of the Olfactory Marker Protein (OMP) Gene in River Dolphins and other Odontocete Cetaceans
  PY  - 2017
  KW  - anosmia
  KW  - Cetacea
  KW  - echolocation
  KW  - Odontoceti
  KW  - olfaction
  KW  - olfactory marker protein
  UR  - http://dx.doi.org/
  N2  - Various toothed whales (Odontoceti) are unique among mammals in lacking olfactory bulbs as adults and are thought to be anosmic (lacking the olfactory sense). At the molecular level, toothed whales have high percentages of pseudogenic olfactory receptor genes, but species that have been investigated to date retain an intact copy of the olfactory marker protein gene (OMP), which is highly expressed in olfactory receptor neurons and may regulate the temporal resolution of olfactory responses. One hypothesis for the retention of intact OMP in diverse odontocete lineages is that this gene is pleiotropic with additional functions that are unrelated to olfaction. Recent expression studies provide some support for this hypothesis. Here, we report OMP sequences for representatives of all extant cetacean families and provide the first molecular evidence for inactivation of this gene in vertebrates. Specifically, OMP exhibits independent inactivating mutations in six different odontocete lineages: four river dolphin genera (Platanista, Lipotes, Pontoporia, Inia), sperm whale (Physeter), and harbor porpoise (Phocoena). These results suggest that the only essential role of OMP that is maintained by natural selection is in olfaction, although a non-olfactory role for OMP cannot be ruled out for lineages that retain an intact copy of this gene. Available genome sequences from cetaceans and close outgroups provide evidence of inactivating mutations in two additional genes (CNGA2, CNGA4), which imply further pseudogenization events in the olfactory cascade of odontocetes. Selection analyses demonstrate that evolutionary constraints on all three genes (OMP, CNGA2, CNGA4) have been greatly reduced in Odontoceti, but retain a signature of purifying selection on the stem Cetacea branch and in Mysticeti (baleen whales). This pattern is compatible with the ?echolocation-priority? hypothesis for the evolution of OMP, which posits that negative selection was maintained in the common ancestor of Cetacea and was not relaxed significantly until the evolution of echolocation in Odontoceti. 
  L3  - 
  JF  - Molecular Phylogenetics and Evolution
  VL  - 
  IS  - 
  ER  -