Analysis of the genetic diversity of the opsin of an Amazonian fish species, the sailfin tetra. Crenuchus spilurus

Differences in underwater lighting conditions usually drive divergence in the visual system, especially in color sensitivity. Amazon small forest streams, locally named igarapes, can be classified into black and clear water types. These water types are remarkable differences in relation to light transmission. Black waters are red-biased environments, while clear waters do not show any apparent bias, being mostly transparent. The sailfin tetra Crenuchus spilurus is a sexually dimorphic Amazon fish species that lives in black and clear water types. In this project, we investigated the genetic divergence of the LWS (Long Wavelength Sensitivity) gene, which is responsible for sensing red color, among populations exposed to black and clear water igarapes. We also estimated the maximum light peak absorption among individuals living in clear and black water types.

水下光照环境的差异通常会驱动视觉系统发生分化，尤以色敏特性的变化最为突出。亚马孙小型林间溪流（当地称为igarapes）可划分为黑水型与清水型两类，二者在光传导特性上存在显著差异：黑水型水体的光谱环境偏向红光，而清水型水体无明显光谱偏向，整体近乎透明。帆鳍脂鲤（Crenuchus spilurus）是一种具有性二态性的亚马孙鱼类，可栖息于黑水型与清水型igarapes溪流中。本研究针对栖息于两类水体的种群，对负责红光感知的LWS（Long Wavelength Sensitivity，长波长敏感）基因的遗传分化展开了调查；同时还估算了栖息于两类水体的个体的最大光吸收峰值。