title: Adaptive evolution of the circadian gene timeout in insects.
abstract: Most insects harbor two paralogous circadian genes, namely timeout and timeless. However, in the Hymenoptera only timeout is present. It remains unclear whether both genes, especially timeout in hymenopteran insects, have distinct evolutionary patterns. In this study, we examine the molecular evolution of both genes in 25 arthropod species, for which whole genome data are available, with addition of the daily expression of the timeout gene in a pollinating fig wasp, Ceratosolen solmsi (Hymenoptera: Chalcidoidea: Agaonidae). Timeless is under stronger purifying selection than timeout, and timeout has positively selected sites in insects, especially in the Hymenoptera. Within the Hymenoptera, the function of timeout may be conserved in bees and ants, but still evolving rapidly in some wasps such as the chalcids. In fig wasps, timeout is rhythmically expressed only in females when outside of the fig syconium but arrhythmically in male and female wasps inside the syconium. These plastic gene expressions reflect adaptive differences of males and females to their environment.
authors.affiliation: 1] Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China [2] University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Gu
authors.affiliation: Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Xiao
authors.affiliation: Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, 571737, China.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Niu
authors.affiliation: Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, 571737, China.
authors.forename: Guang-Chang
authors.initials: GC
authors.lastname: Ma
authors.affiliation: Statistics and Mathematics College, Yunnan University of Finance and Economics, Kunming, Yunnan, 650221, China.
authors.forename: Derek W
authors.initials: DW
authors.lastname: Dunn
authors.affiliation: 1] Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China [2] Plant Protection College, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Huang
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000818:Animals; D005075:Biological Evolution; D002940:Circadian Rhythm / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D017344:Genes, Insect; D007313:Insecta / Q000145:classification / Q000502:physiology*; D008297:Male; D010802:Phylogeny; D012641:Selection, Genetic