Cytogenetic investigation of Arctic char × brook trout F1, F2 and backcross hybrids revealed remnants of the chromosomal rearrangements

Journal of Applied Genetics ◽

10.1007/s13353-020-00584-2 ◽

2020 ◽

Author(s):

Konrad Pomianowski ◽

Konrad Ocalewicz

Keyword(s):

Brook Trout ◽

Parental Species ◽

Salvelinus Alpinus ◽

Chromosomal Rearrangements ◽

Backcross Progeny ◽

Arctic Char ◽

Gene Pools ◽

Hybrid Progeny ◽

Telomeric Sequences ◽

Backcross Hybrids

Abstract Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) hybridize and their offspring is viable and fertile. This may be a real treat for the native European stocks of Arctic char which gene pools might be unintendedly contaminated with the genetic elements of brook trout. On the other hand, hybrids of these two species are appreciated by customers and have some potential for the aquaculture. Moreover, Salvelinus hybrids and backcross individuals are interesting models in the research focused on influence of hybridization on the genomic organization and chromosome rearrangements. Thus, the main goal of the present study was to examine chromosomes of Arctic char × brook trout F1, F2 hybrids and backcross individuals and compare with genomic information concerning parental species to recognize karyotypic changes provoked by the hybridization events. Application of conventional and molecular (FISH) techniques allow to identify characteristic chromosomes for both parental species in the hybrid progeny and show multiplicity of cytotypes among different types of crosses with variability in structure and number of chromosome (81–85) and chromosome arm (99–101). Chromosome fragment was detected in the karyotype of one F1 and one backcross individual and the presence of one triploid (3n) fish was documented. Occurrence of chromosomes containing internally located telomeric sequences (ITS) inherited after brook trout or both parental species was shown in F1 and backcross progeny. Moreover, additional CMA3-positive signal on chromosome from Arctic char pair no. 2 in F1 fish and interstitially located active NOR visible on subtelo-acrocentric (F2 hybrid) and acrocentric (Sf × H individual) chromosomes were detected. Described polymorphic chromosomes together with specific, interstitial location of CMA3-positive found in F2 and Sf × H hybrids and DAPI-positive regions observed in H × Sa fish at different uniarmed chromosomes pair presumably are remnants of chromosomal rearrangements. Provided results strongly indicate that the hybridization process influenced the genome organization in the Salvelinus hybrid progeny.

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Natural Hybridization between Arctic Char (Salvelinus alpinus) and Brook Trout (S. fontinalis): Evidence from Northern Labrador

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f91-171 ◽

1991 ◽

Vol 48 (8) ◽

pp. 1437-1445 ◽

Cited By ~ 37

Author(s):

Johan Hammar ◽

J. Brian Dempson ◽

Eric Verspoor

Keyword(s):

Research And Development ◽

Brook Trout ◽

Parental Species ◽

Salvelinus Alpinus ◽

Electrophoretic Analysis ◽

Arctic Char ◽

Natural Hybridization ◽

Gene Pools ◽

Fraser River ◽

Species Hybrids

Electrophoretic analysis of successive samples of Salvelinus collected in the Fraser River watershed of northern Labrador in 1984 and 1986 revealed the existence of natural hybrids between Arctic char (Salvelinus alpinus) and brook trout (S. fontinalis). We examined 11 electrophoretic loci in liver tissue; 10 loci were informative and six were diagnostic of the two species and their hybrids. The electrophoretic phenotypes of some hybrid specimens sugested that they were second-generation hybrids and/or backcrosses to the parental species. Hybrids were represented by six different year classes, indicating that crossing between the species in the system is a regular occurrence. The hybrids, although visually difficult to distinguish from brook trout, were meristicaîly intermediate or more closely resembled Arctic char. The observations raise a number of questions regarding the ecological circumstances promoting hybridization in the evolution of Arctic char and brook trout populations. The results stress the need for restrictions on introducing brook trout into systems with original populations of Arctic char. Further, Arctic char from the Fraser River are commonly used for aquaculture research and development; therefore, there is a clear need to screen fish carefully to determine whether or not they represent introgressed gene pools.

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ANDROGENETIC DEVELOPMENT OF BROOK TROUT (SALVELINUS FONTINALIS MITCHILL), ARCTIC CHAR (SALVELINUS ALPINUS L.) AND THEIR HYBRIDS

Indian Journal of Science and Technology ◽

10.17485/ijst/2011/v4is.149 ◽

2011 ◽

Vol 4 (is1) ◽

pp. 232-233

Author(s):

Ocalewicz K

Keyword(s):

Brook Trout ◽

Salvelinus Fontinalis ◽

Salvelinus Alpinus ◽

Arctic Char

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Cytogenetic identification of genomic elements of brook trout ( Salvelinus fontinalis ) in the karyotype of Arctic char ( Salvelinus alpinus ) from the aquaculture broodstock

Journal of Applied Ichthyology ◽

10.1111/jai.13913 ◽

2019 ◽

Cited By ~ 1

Author(s):

Konrad Pomianowski ◽

Małgorzata Jankun ◽

Konrad Ocalewicz

Keyword(s):

Brook Trout ◽

Salvelinus Fontinalis ◽

Salvelinus Alpinus ◽

Arctic Char

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Detection of interstitial telomeric sequences in the Arctic charr (Salvelinus alpinus) (Teleostei: Salmonidae)

Genome ◽

10.1139/g11-073 ◽

2012 ◽

Vol 55 (1) ◽

pp. 26-32 ◽

Cited By ~ 6

Author(s):

K. Pomianowski ◽

M. Jankun ◽

K. Ocalewicz

Keyword(s):

Chromosome Number ◽

Brook Trout ◽

Lake Trout ◽

Salvelinus Alpinus ◽

Arctic Charr ◽

Interindividual Variation ◽

The Arctic ◽

Telomeric Sequences ◽

Interstitial Telomeric Sequences

Highly polymorphic Arctic charr ( Salvelinus alpinus Linnaeus, 1758) chromosomes were studied using conventional and molecular methods. The diploid chromosome number in the studied individuals was 2n = 81 or 2n = 82, with a fundamental arm number (NF) = 100. These differences are due to Robertsonian fusions. Interindividual variation in the number and size of DAPI and CMA3 positively stained chromatin sites was observed in studied specimens. In the case of two individuals, the subtelomeric region of the long arm (q) of the largest acrocentric chromosome (chromosome number 10) was positively stained by CMA3 fluorochrome. Both primed in situ labelling (PRINS) and fluorescence in situ hybridization (FISH) revealed that this CMA3-positive region was flanked by telomeric sequences. Previously, the subterminal position of interstitial telomeric sequences located in the vicinity of the CMA3-positive guanine-rich chromatin have been described in two other Salvelinus species, brook trout ( Salvelinus fontinalis ) and lake trout ( Salvelinus namaycush ). Moreover, multichromosomal location and variation in size of CMA3 bands have been observed in various Salvelinus taxa, including fishes with internally located telomeric sequences. These results suggest that relocation of CMA3-positive chromatin segments in these species may be facilitated by flanking interstitial telomeric sequences (ITSs).

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Epidermis structure in the brook trout (Salvelinus fontinalis) and its Arctic char (Salvelinus alpinus) hybrid

Acta Veterinaria Brno ◽

10.2754/avb201584020159 ◽

2015 ◽

Vol 84 (2) ◽

pp. 159-166

Author(s):

Karel Halačka ◽

Radovan Kopp ◽

Ondřej Klíma ◽

Jan Mareš

Keyword(s):

Brook Trout ◽

Skin Infection ◽

Salvelinus Fontinalis ◽

Salvelinus Alpinus ◽

Relative Proportion ◽

Arctic Char ◽

Secretory Cells ◽

Epidermal Thickness ◽

Epidermal Structure ◽

Epidermis Structure

Brook trout (Salvelinus fontinalis) is a species of fish native to North-East America. Brook trout are also commercially raised in large numbers for food production. Skin infection and/or parasite outbreaks can have a serious economics effect on aquaculture businesses. For this reason, it has been hybridized with the more resistant Arctic char (Salvelinus alpinus). The aim of this study was an examination of the epidermal structure and dynamic in brook trout and its Arctic char hybrid which is less sensitive to skin infection. The samples of fish (72 brook trout, 72 brook trout × Arctic char hybrid) from fish farm in Pravíkov (49°19’10”N, 15°5’40”E) were collected five times during the year 2011. Absolute and relative epidermal thickness (in relation to body size) and relative proportion of secretory cells in a given volume of epidermis were measured. The epidermis structure of brook trout and brook trout × Arctic char hybrid both display similar seasonal dynamics, with a decrease in absolute and relative epidermal thickness and a reduction in the relative percentage of mucous secretory cells over the summer. On the other hand, the lower absolute (mean 103 µm (range 84–146 µm) in brook trout; 88 µm (range 68–115 µm) in hybrids) and relative epidermal thickness (mean 4.8 (range 3.6–6.8) in brook trout; 4.4 (range 2.9–6.4) in hybrids) and lower volume of secretory cells was observed to the hybrid (mean 28% (range 19–33%) in brook trout; 23% (range 10–30%) in hybrids). It can interrelate with their higher resistance to infection and/or parasite outbreaks.

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Introgression and fixation of Arctic char (Salvelinus alpinus) mitochondrial genome in an allopatric population of brook trout (Salvelinus fontinalis)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-018 ◽

1995 ◽

Vol 52 (1) ◽

pp. 179-185 ◽

Cited By ~ 156

Author(s):

Louis Bernatchez ◽

Hélène Glémet ◽

Chris C. Wilson ◽

Roy G. Danzmann

Keyword(s):

Mitochondrial Genome ◽

Brook Trout ◽

Salvelinus Fontinalis ◽

Salvelinus Alpinus ◽

Introgressive Hybridization ◽

Rflp Analysis ◽

Arctic Char ◽

Long Term Effects ◽

Ancestral Polymorphism ◽

Mitochondrial Genotype

Although mitochondrial introgression between taxa has been increasingly documented, interspecific replacement of mtDNA is rare, particularly when the donor species is absent. We document evidence for a population of brook trout (Salvelinus fontinalis) in which all individuals possess the mitochondrial genome of Arctic char (S. alpinus) despite the present-day absence of the latter species in the watershed where the population is located. The mitochondrial genotype of 48 brook trout from Lake Alain (Québec) was characterized by RFLP analysis performed over the entire mtDNA molecule and/or a 2.5-kb PCR-amplified segment of the ND-5/6 region. Although the fish examined were morphologically indistinguishable from typical brook trout and homozygous for the diagnostic alleles characteristic of brook trout, the mtDNA of all individuals was identical to the Québec Arctic char haplotype. Together, these results indicate that the mtDNA haplotype observed in Lake Alain brook trout has resulted from ancient introgression with Arctic char rather than ancestral polymorphism or convergent evolution. They also demonstrate that introgressive hybridization between those two species can have significant and long-term effects on their genetic composition.

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Host specificity and geographical distribution ofEubothriumin European salmonid fish

Journal of Helminthology ◽

10.1079/joh2003188 ◽

2003 ◽

Vol 77 (3) ◽

pp. 255-262 ◽

Cited By ~ 13

Author(s):

T. Scholz ◽

R. Kuchta ◽

A.P. Shinn ◽

V. Šnábel ◽

V. Hanzelová

Keyword(s):

Host Specificity ◽

Brook Trout ◽

Lake Trout ◽

Salvelinus Fontinalis ◽

Salvelinus Alpinus ◽

Arctic Char ◽

Salmonid Fish ◽

Coregonus Albula ◽

Geographical Regions ◽

South Eastern Europe

AbstractThe host specificity and distribution ofEubothrium crassum(Bloch, 1779) andEubothrium salvelini(Schrank, 1790), morphologically fairly similar pseudophyllidean tapeworms parasitizing salmonid fish, were critically assessed on the basis of morphological and genetic evaluation of extensive material collected from different definitive hosts and geographical regions in Europe.Eubothrium crassumoccurs in fish of the generaSalmo, i.e. salmon (S. salar– both freshwater and marine), sea trout (S. trutta trutta), brown trout (S. truttafario), and lake trout (S. truttalacustris), and also in Danubian salmon (Hucho hucho) and vendace (Coregonus albula).Eubothrium salveliniparasitizes Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in Europe, and also whitefish (Coregonus wartmanni). Rainbow trout (Oncorhynchus mykiss), which is not a native European fish species, was found to be a suitable definitive host for bothEubothriumspecies, which may occur simultaneously in the same fish. Previous records ofE. crassumin Arctic char and brook trout, and those ofE. salveliniin fish of the genusSalmowere most probably misidentifications. Most studies ofEubothriumhave involved salmonids from the northern part of Europe, with few records from southern and south-eastern Europe. This study also confirmed the reliability of the morphology of the apical disc for the discrimination ofE. crassumandE. salvelini.

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