Distribution of five growth hormone gene haplogroups in wild and cultured tench, Tinca tinca L., populations

Abstract

Summary Tench, Tinca tinca L., has a growth hormone (GH) gene of 1758–1763 bp in length with at least 13 different haplotypes and 14 polymorphic sites (PS). Fragment length analysis at PS 1 and 7 with indels, and PCR‐RFLP analysis at PS 5 and 13 with single nucleotide polymorphisms (SNPs) distinguish five GH gene haplogroups (H1‐H3 belonging to the Western, W, and H4‐H5, to the Eastern, E, phylogroup). Using quick and inexpensive screening assays, the aim of the study was to determine the allelic and genotypic distribution of the five GH gene haplogroups across 16 wild and cultured tench populations originating from all major parts of its distribution range. The mean observed number of haplogroups per population was 3.125. The most frequent haplogroup was H5 (0.482); the least frequent was H4 (0.022). The W haplogroups were observed in 12 out of the 16 populations, but no population had only the W haplogroup. With two exceptions (Ital and Kowa), the E haplogroups were observed in most populations as well as unique in three populations (Chin, Bada and Turk). Hardy–Weinberg equilibrium tests revealed heterozygote excess (P < 0.05) in four populations (Felc, ML98, Ta98 and Vo98) whereas heterozygote deficiency was not observed. Overall F‐statistics showed quite a high degree of differentiation (P < 0.01) of tench populations, as the global FST was 0.212. The pairwise FST values ranged from 0.0 to 0.726. Non‐significant differences between pairs of populations were observed in 41 cases (36.6%). Nei's standard genetic distances displayed large variations, ranging from 0.0 (between Bada and Chin) to 2.572 (between Turk and Ital). In some cases, similarities between populations from distant countries and dissimilarities between populations from the same country were observed. The Neighbour‐Joining tree based on Nei's standard genetic distances showed two major clades corresponding with the observed frequencies of haplogroups within populations.

Genetic structure and divergence of tench Tinca tinca European populations

“…Tench has a great potential for aquaculture (Celada et al ., 2007; Gela et al ., 2006), but there is limited information on its genetic structure compared to other fish species (Lo Presti et al ., 2012). So far, genetic diversity within and between tench populations relied on enzyme variability (Kohlmann & Kersten, 1998), microsatellite markers (Kohlmann et al ., 2007, 2010; Kohlmann & Kersten, 2006) and nuclear and mtDNA (Lajbner et al ., 2010, 2011; Lajbner & Kotlík, 2011; Lo Presti et al ., 2010, 2012, 2014; Lujić et al ., 2017), as well as genes of growth hormones (Kocour & Kohlmann, 2014). The analysis of polymorphisms on nuclear markers and mtDNA regions is verified as an exceptional tool in the detection of genetic variability among tench species (Briolay et al ., 1998; Lo Presti et al ., 2010, 2012).…”

A novel transcriptome-derived SNPs array for tench (Tinca tinca L.)

“…Both breeds, containing approximately 120 adult individuals, have been maintained to date by intra-linear mating only for 6 generations. Previous studies on these fish have shown that both breeds have gene pools mixed of both Western and Eastern phylogroups [ 22 , 45 ]. The transcriptome changes according to genes expressed.…”

“…For genome sequencing, a total of ten tench individuals from six different locations were collected ( S2 Table ) in order to cover maximal available genetic diversity, including phylogroup origin of tench species. Samples were taken from the tench tissue collection of Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany and they represented populations throughout Neighbor-joining trees inferred from studies focused on genetic diversity of the growth hormone (GH) gene [ 22 ], microsatellites [ 17 ] and mitochondrial DNA [ 18 ].…”

“…Genetic studies on tench have until now been based on allozymes [ 14 , 15 ], microsatellites [ 16 , 17 ], PCR-RFLP [ 18 , 19 ] and sequence polymorphism of genes and DNA fragments [ 20 – 22 ]. These studies have revealed the existence of Western and Eastern phylogroups [ 6 , 19 ].…”

“…and successfully applied in other fish species [ 38 , 43 ]. The SNPs array was then used to disentangle the population genetic structure of two cultured tench breeds (Tabor and Hungarian), previously identified as stocks representing mixture of haplotypes out of both phylogroups [ 22 ].…”