Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017
Erindi/veggspjald / Talk/poster E90
Höfundar / Authors: Jóhannes Guðbrandsson (1,2), Kalina. H. Kapralova (1), Sigríður R. Franzdóttir (1), Völundur Hafstað (1), Þóra M. Bergsveinsdóttir (1), Zophonías O. Jónsson (1), Sigurður Snorrason (1), Arnar Pálsson (1)
Starfsvettvangur / Affiliations: 1. Líf- og Umhverfisvísindastofnun Háskóla Íslands, 2. Hafrannsóknastofnun, rannsókna- og ráðgjafarstofnun hafs og vatna
Kynnir / Presenter: Jóhannes Guðbrandsson
The four morphs of Lake Thingvallavatn are a one of the best known examples of resource polymorphism in Arctic charr. The morphs differ in various traits, including feeding preferences, life history, spawning ground and time, body color and head morphology. The morphs have been shown to differ genetically although being more related to each other than to other charr populations in Iceland. Until now genome wide studies of their genetic variability have been lacking. We recently performed a RNA-sequencing study to look at gene expression among three of the four morphs in early development using pooled samples (Jóhannes Guðbrandsson et al, 2017 submitted). In addition to looking at gene expression, the data can also been used to look at genetic variation. We discovered 19,252 polymorphic variants in the RNA-seq data. The morphs could be easily separated using the genetic data and 2331 variants showed high divergence among the three morphs (Fst above 0.2). The two benthic morphs (small and large benthic) were more closely related to each other than to the planktivorous morph. When mapped to the genomes of related salmonid species, highly divergent variants were spread over multiple chromosomes indicating that natural selection occurred on multiple linkage groups. From the set of highly diverged variants, 22 were confirmed to be polymorphic in a population sample that also included the fourth morph (piscivorous). The divergence among morphs was also confirmed in all but three of the variants. Our results indicate that the morphs have been reproductively isolated for multiple generations with only minor gene flow between them. This has allowed selection to operate on various part of the genome instead of being restricted to areas of low recombination.