Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster E30

Investigating genomic and phenotypic divergence among sympatric Arctic charr morphs in the Lake Thingvallavatn-Úlfljótsvatn system

Höfundar / Authors: Han Xiao(1), Benjamin Sigurgeirsson(1), Johannes Gudbrandsson(2), Zophonias O. Jonsson(1), Arnar Palsson(1), Sigurdur S. Snorrason(1)

Starfsvettvangur / Affiliations: 1.Faculty of Life and Environmental Science, University of Iceland, Sturlugötu 7,101 Reykjavík, Iceland, 2. Marine and Freshwater Research Institute (MFRI), Skúlagata 4 101 Reykjavík, Iceland

Kynnir / Presenter: Han Xiao

Coexistence of phenotypic and ecological distinct morphs has been widely reported in salmonids. In contrast to substantial interest in associating this phenomenon with tropic polymorphism and ecological speciation, the genetic basis regarding the emergence and maintenance of such divergence is largely unexplored. Here we investigate the extent of phenotypical and genome-wide genetic differentiation and connectivity among the Arctic charr morphs in Lake Thingvallavatn, and the smaller, downstream Lake Úlfljótsvatn. While the phenotypic divergence of the four charr morphs in Lake Thigvallavatn has been well observed and recorded, the patterns in Lake Úlfljótsvatn appear not to be as clear. Using filtered SNPs acquired via ddRADseq we found that the genetic differentiation between morphs is stronger in Lake Thingvallavatn than in Lake Úlfljótsvatn (mean FST =0.06 vs FST= 0.014). The differentiation between fish of the same morphs from the two lakes showed intermediate levels (FST = 0.026). Morphological analysis also revealed more intermediate-morph individuals in Lake Úlfljótsvatn than in Lake Thingvallavatn. Furthermore, besides only a few benthic-like individuals that tightly clustered with the small benthic morph from the Lake Thingvallavatn, no presence of distinguished small benthic morph in the Lake Úlfljótsvatn was supported in this study. Therefore, asymmetric gene flow would rather probably occur mostly downstream from Thingvallavatn to Úlfljótsvatn. However, to keep intraspecific diversity in Lake Úlfljótsvatn may be complex and dependents on habitat availability and resource use.