RESUMEN
Three species of seabreams, Acanthopagrus berda, Acanthopagrus schlegelii and Pagrus major, living at different depths, were chosen to investigate how visual spectra and opsin genes evolve in response to various photic environments. The lambda max of photoreceptors and opsin genes were measured and cloned from these species. Eight to twelve nm spectral shifts in the rod and blue cone cells were observed between the deep-sea, P. major, and shallow-sea species, A. berda and A. schlegelii. Furthermore, the deep-sea P. major has lost its red light vision. Six opsin genes, Rh1, Rh2A, Rh2B, SWS1, SWS2 and LWS, were identified from all three seabream species, with the LWS genes of P. major having undergone pseudogenization. These data indicate that the photic environment of habitats select for the physiology of visual spectra and coding of opsin genes.
Asunto(s)
Evolución Molecular , Opsinas de Bastones/genética , Dorada/genética , Adaptación Biológica , Animales , Secuencia de Bases , Clonación Molecular , Estilo de Vida , Filogenia , Células Fotorreceptoras Retinianas Conos/fisiología , Células Fotorreceptoras Retinianas Conos/ultraestructura , Dorada/fisiología , Análisis de Secuencia de ADN , Especificidad de la Especie , EspectrofotometríaRESUMEN
Toll-like receptors (TLRs) have been identified as key sensors of invading microbes by identifying pathogen-associated molecular patterns and activating innate immune responses. Whereas purifying selection has been suggested in mammalian TLR9, evolutionary features of TLR9 in teleosts have not been investigated in detail. We therefore analysed TLR9 DNA sequences of eight teleost species, including zebrafish (Danio rerio), Japanese flounder (Paralichthys olivaceus), pufferfish (Takifugu rubripes), and five seabreams. Eleven sites subjected to positive selection were identified using the codon-substitution models of PAML 3.15. Ten of these 11 sites were found to be associated with leucine-rich repeats (LRRs). Seven of these 10 positively selected sites were associated with the convex surface of the LRR solenoids, leading to variations of the structures of the LRRs possibly by the introduction of flexibility into the LRR solenoids. The positive selection of LRRs in TLR9 may indicate the adaptation of teleosts to different oligodeoxynucleotides present in different bacterial species.