Abstract
BackgroundBody weight and length are economically important traits in foodfish species influenced by quantitative trait loci (QTL) and environmental factors. It is usually difficult to dissect the genetic and environmental effects. Asian seabass (Lates calcarifer) is an important marine foodfish species with a compact genome (~700 Mb). The recent construction of a first generation linkage map of Asian seabass with 240 microsatellites provides a good opportunity to determine the number and position of QTL, and the magnitude of QTL effects with a genome scan.ResultsWe conducted a genome scan for QTL affecting body weight, standard length and condition factors in an F1 family containing 380 full-sib individuals from a breeding stock by using 97 microsatellites evenly covering 24 chromosomes. Interval mapping and multiple QTL model mapping detected five significant and 27 suggestive QTL on ten linkage groups (LGs). Among the five significant QTL detected, three (qBW2-a, qTL2-a and qSL2-a) controlling body weight, total and standard length respectively, were mapped on the same region near Lca287 on LG2, and explained 28.8, 58.9 and 59.7% of the phenotypic variance. The other two QTL affecting body weight, qBW2-b and qBW3, were located on LG2 and 3, and accounted for 6.4 and 8.8% of the phenotypic variance. Suggestive QTL associated with condition factors are located on six different LGs.ConclusionThis study presents the first example of QTL detection for growth-related traits in an F1 family of a marine foodfish species. The results presented here will enable further fine-mapping of these QTL for marker-assisted selection of the Asian seabass, eventually identifying individual genes responsible for growth-related traits.
Highlights
Body weight and length are economically important traits in foodfish species influenced by quantitative trait loci (QTL) and environmental factors
We demonstrated that body weight at 90 day post-hatch was significantly correlated with body weight at harvest (289 dph) in Asian seabass [29]
The average condition factors (KTL and KSL) were 1.49 ± 0.12 and 2.64 ± 0.22 calculated according to total length (TL) and standard lengths (SL) respectively (Table 1)
Summary
Body weight and length are economically important traits in foodfish species influenced by quantitative trait loci (QTL) and environmental factors. Asian seabass (Lates calcarifer) is an important marine foodfish species with a compact genome (~700 Mb). Asian seabass (Lates calcarifer), called Barramundi in Australia, is an important farmed marine foodfish species which has been cultured for more than 20 years in Southeast Asian countries [1]. Australia is presently becoming a major producer The production of this species is expected to expand more rapidly in the few years due to high market demand. [3,4], while studies using polymorphic microsatellites showed that both cultured and wild stocks of Asian seabass in Southeast Asia contained high allelic and gene diversity [5,6].
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