A European whitefish linkage map and its implications for understanding genome-wide synteny between salmonids following whole genome duplication

Abstract

Genomic datasets continue to increase in size and ease of production for a wider selection of species including non-model organisms. For many of these species highly contiguous and well-annotated genomes are unavailable due to their prohibitive complexity and cost. As a result, a common starting point for genomic work in non-model species is the production of a linkage map, which involves the grouping and relative ordering of genetic markers along the genome. Dense linkage maps facilitate the analysis of genomic data in a variety of ways, from broad scale observations regarding genome structure e.g. chromosome number and type or sex-related structural differences, to fine scale patterns e.g. recombination rate variation and co-localisation of differentiated regions. Here we present both a sex-averaged and sex-specific linkage maps for Coregonus sp. \"Albock\" containing 5395 single nucleotide polymorphism (SNP) loci across 40 linkage groups to facilitate future investigation into the genomic basis of whitefish adaptation and speciation. The map was produced using restriction-site associated digestion (RAD) sequencing data from two wild-caught parents and 156 F1 offspring in Lep-MAP3. We discuss the differences between our sex-avagerated and sex-specific maps and identify synteny between C. sp. \"Albock\" linkage groups and the Atlantic salmon (Salmo salar) genome. Our synteny analysis confirms that many patterns of homology observed between Atlantic salmon and Oncorhynchus and Salvelinus species are also shared by members of the Coregoninae subfamily.