Study of ecological and developmental divergence of Icelandic Arctic charr (Salvelinus alpinus) at different scales

Arctic charr (Salvelinus alpinus) has been called the most variable vertebrate on the planet. It is highly diverse in morphology (size, color, and form), behavior, life history, and ecology. Lake Thingvallavatn, the biggest natural waterbody in Iceland, harbours four sympatric morphs. Moreover, allopatric charr populations in the country differ substantially. This thesis focuses on ecological variation within species on different scales, size, geology and time. Specific genetic variations in the genome and the expression of candidate genes during development in sympatric morphs of Thingvallavatn were studied in manuscript one, and variation in life-history traits in diverse populations, either in sympatry or in different watersheds, that differ in evolutionary age was analyzed, in the second manuscript. The work involved bioinformatic analyses, qPCR, otolith imaging and age-determination and various statistical analyses. The results revealed differentially expressed (Sting, Hvcn1, and Med4) genes close to (