caa a22 4500 445820969 CHVBK 20180317145244.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s00239-011-9481-0 doi (NATIONALLICENCE)springer-10.1007/s00239-011-9481-0 Wooding Stephen McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, 75390-8591, Dallas, TX, USA aut Signatures of Natural Selection in a Primate Bitter Taste Receptor [Elektronische Daten] [Stephen Wooding] Bitter taste receptors (TAS2Rs) enable animals to detect and avoid toxins in the environment, including noxious defense compounds produced by plants. This suggests that TAS2Rs are under complex pressures from natural selection. To investigate these pressures, we examined signatures of selection in the primate TAS2R38 gene. Whole-gene (1,002bp) sequences from 40 species representing all major primate taxa uncovered extensive variation. Nucleotide substitutions occurred at 448 positions, resulting in 201 amino acid changes. Two single-nucleotide deletions, one three-nucleotide in-frame deletion, and one premature stop codon were also observed. The rate of non-synonymous substitution (ω=dN/dS), was high in TAS2R38 (ω=0.60) compared to other genes, but significantly lower than expected under neutrality (P=4.0×10−9), indicating that purifying selection has maintained the basic structure of the receptor. However, differences were present among receptor subregions. Non-synonymous rates were significantly lower than expected in transmembrane domains (ω=0.55, P=1.18×10−12) and internal loops (ω=0.51, P=7.04×10−5), but not external loops (ω=1.16, P=0.53), and evidence of positive selection was found in external loop 2, which exhibited a high rate (ω=2.53) consistent with rapid shifts in ligand targeting. These patterns point to a history of rapid yet constrained change in bitter taste responses in the course of primate evolution. Springer Science+Business Media, LLC, 2012 Bitter nationallicence TAS2R nationallicence Receptor nationallicence Primate nationallicence Selection nationallicence Journal of Molecular Evolution Springer-Verlag 73/5-6(2011-12-01), 257-265 0022-2844 73:5-6<257 2011 73 239 https://doi.org/10.1007/s00239-011-9481-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00239-011-9481-0 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Wooding Stephen McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, 75390-8591, Dallas, TX, USA aut NATIONALLICENCE 773 0- Journal of Molecular Evolution Springer-Verlag 73/5-6(2011-12-01), 257-265 0022-2844 73:5-6<257 2011 73 239 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer