Production and verification of the first Atlantic salmon (Salmo salar L.) clonal lines

Tom Johnny Hansen,Anders Thorsen,Thomas William Kenneth Fraser,Kevin Alan Glover,Anne Grete Eide Sørvik,Tone Vågseth,David Penman,Per Gunnar Fjelldal

doi:10.1186/s12863-020-00878-8

Tom Johnny Hansen, Anders Thorsen + Show 6 more

Open Access

https://doi.org/10.1186/s12863-020-00878-8

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Abstract

BackgroundIn several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. These lines are standardized and can be reproduced over generations. In rainbow trout such lines have existed for decades and has become important research tools in genome studies as well as in studies of commercially important traits. The Atlantic salmon is one of the best studied fish species globally, but all experiments are done on fish of wild or domesticated origin and access to standardized immortal fish lines would be of great benefit. Here, we describe the protocols developed to produce mitotic gynogenes, and from these the first clonal lines in Atlantic salmon.ResultsAtlantic salmon eggs fertilized with UV irradiated sperm combined with a pressure shock applied at 4700–4800 minC at 8 °C gave all homozygous (doubled haploid) gynogenetic progeny with high survival. From the six first maturing females, five all homozygous clonal lines were produced by meiotic gynogenesis and were verified as clonal and identical to their mother with microsatellite markers.ConclusionsWe have now produced the first documented cloned Atlantic salmon lines. This work demonstrates the potential for production of further Atlantic salmon clonal lines, potentially with distinct characteristics. Such lines will provide an important resource for further elucidation of phenotypic and genetic traits in this globally important species.

Highlights

In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques
Different rainbow trout clones show a wide range of susceptibility to viruses like the infectious salmon anaemia virus [14], the rhabdoviruses viral haemorrhagic septicaemia virus (VHSV) and infectious haematopoietic necrosis virus (IHNV) [15], and have been used to identify a major QTL for resistance to VHSV [16]
In the present study we describe the development of a protocol for production of Atlantic salmon mitotic gynogenetic fish, and compare their growth with outbred progeny from the same broodfish and describe their phenotypic development and sexual maturation

Summary

Introduction

In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. In rainbow trout, doubled haploid and clonal lines were established early (see [7, 8]) and have been utilized in the production of linkage maps [10, 11], detection of QTLs for meristic traits [12] and investigations of developmental rate [13]. They have proved valuable in detailed analysis of commercially important traits such as disease resistance and Hansen et al BMC Genetics (2020) 21:71 utilization of animal contra vegetable dietary sources. A follow-up study describe how an early short-term exposure of fry improved the acceptance and utilisation of the same diet at a later life stage [19]

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