A Microsatellite Genetic Map of the Turbot (Scophthalmus maximus)

Abstract

A consensus microsatellite-based linkage map of the turbot (Scophthalmus maximus) was constructed from two unrelated families. The mapping panel was derived from a gynogenetic family of 96 haploid embryos and a biparental diploid family of 85 full-sib progeny with known linkage phase. A total of 242 microsatellites were mapped in 26 linkage groups, six markers remaining unlinked. The consensus map length was 1343.2 cM, with an average distance between markers of 6.5 6 0.5 cM. Similar length of female and male maps was evidenced. However, the mean recombination at common intervals throughout the genome revealed significant differences between sexes, $1.6 times higher in the female than in the male. The comparison of turbot microsatellite flanking sequences against the Tetraodon nigroviridis genome revealed 55 significant matches, with a mean length of 102 bp and high sequence similarity (81-100%). The comparative mapping revealed significant syntenic regions among fish species. This study represents the first linkage map in the turbot, one of the most important flatfish in European aquaculture. This map will be suitable for QTL identification of productive traits in this species and for further evolutionary studies in fish and vertebrate species.

Identification of the Major Sex-Determining Region of Turbot (Scophthalmus maximus)

“…Families were obtained following a three-generation scheme starting from unrelated grandparents coming from natural populations of the Atlantic Ocean. Two families were used for QTL identification using a large number of markers: Qfam1 (the DF reference family in Bouza et al 2007) constituted 85 individuals (49 females and 36 males) and Qfam2 constituted 38 individuals (20 females and 18 males). Three additional families were used to confirm the QTL detected in Qfamilies by checking the association of the closest QTL markers to sex: Afam1 (39 individuals: 28 females and 11 males), Afam2 (30 individuals: 17 females and 13 males), and Afam3 (73 individuals: 36 females and 37 males).…”

“…In this study, we used the turbot genetic map (Bouza et al 2007Martínez et al 2008) to look for sexassociated QTL in this species. The identification of a major QTL in a specific linkage group (LG) in the five families analyzed prompted us to refine the genetic map at this LG and to perform a comparative genomics approach against model fish species for a precise location and characterization of the putative SD region.…”

Advances in genomics for flatfish aquaculture

“…Moreover, genetic maps provide a useful tool to study genome organization and for gathering information about syntenic relationships across species and identification of putative candidate genes associated with QTLs (Castaño-Sanchez et al 2010;Sarropoulou et al 2008). Although genetic maps have been developed for turbot and Atlantic halibut (Reid et al 2007;Bouza et al 2007), the recent application of NGS has allowed the identification of a high number of genetic markers useful for high-density maps. In the turbot, for instance, the first generation map had 26 linkage groups (LG) based on 242 anonymous microsatellites and with an average marker distance of 6.5 centimorgan (cM) (Bouza et al 2007).…”

“…Although genetic maps have been developed for turbot and Atlantic halibut (Reid et al 2007;Bouza et al 2007), the recent application of NGS has allowed the identification of a high number of genetic markers useful for high-density maps. In the turbot, for instance, the first generation map had 26 linkage groups (LG) based on 242 anonymous microsatellites and with an average marker distance of 6.5 centimorgan (cM) (Bouza et al 2007). Later, a second map using 158 different anonymous markers identified 21 and 30 LG in the male and female maps, respectively, although with higher intermarker spacing (9.9 and 12.9 cM, respectively) (Ruan et al 2010).…”

“…Some flatfishes such as the tongue sole exhibit a pair of morphologically distinct sex chromosomes (WZ/ZZ) (Zhuang et al 2006). However, no sex-linked chromosome heteromorphisms have been described in turbot (Bouza et al 2007) or Senegalese sole (Cross et al 2006). Recently, a sex determining region was located at the proximal end of LG5 in turbot, close to the SmaUSC-E30 marker (Martinez et al 2009).…”