title: The loss of taste genes in cetaceans.
abstract: BACKGROUND
  Five basic taste modalities, sour, sweet, bitter, salt and umami, can be distinguished by humans and are fundamental for physical and ecological adaptations in mammals. Molecular genetic studies of the receptor genes for these tastes have been conducted in terrestrial mammals; however, little is known about the evolution and adaptation of these genes in marine mammals.
  
  
  RESULTS
  Here, all five basic taste modalities, sour, sweet, bitter, salt and umami, were investigated in cetaceans. The sequence characteristics and evolutionary analyses of taste receptor genes suggested that nearly all cetaceans may have lost all taste modalities except for that of salt.
  
  
  CONCLUSIONS
  This is the first study to comprehensively examine the five basic taste modalities in cetaceans with extensive taxa sampling. Our results suggest that cetaceans have lost four of the basic taste modalities including sour, sweet, umami, and most of the ability to sense bitter tastes. The integrity of the candidate salt taste receptor genes in all the cetaceans examined may be because of their function in Na(+) reabsorption, which is key to osmoregulation and aquatic adaptation.
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. zhukangli1989@163.com.
authors.forename: Kangli
authors.initials: K
authors.lastname: Zhu
authors.affiliation: Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA. xmzhou0103@163.com.
authors.forename: Xuming
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. xushixia78@163.com.
authors.forename: Shixia
authors.initials: S
authors.lastname: Xu
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. sundysun9@gmail.com.
authors.forename: Di
authors.initials: D
authors.lastname: Sun
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. kyzhounj@126.com.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Ren
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. kyzhounj@126.com.
authors.forename: Kaiya
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China. gyang@njnu.edu.cn.
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002591:Cetacea / Q000145:classification / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000502:physiology; D012965:Sodium Chloride / Q000378:metabolism; D013650:Taste Buds / Q000502:physiology
chemical_list: D043562:Receptors, G-Protein-Coupled; D012965:Sodium Chloride