http://auburn.edu/academic/agriculture/fisheries/genomics/FISH7660%202006/DNA%20marker%20review%20paper-Aquaculture.pdf

DNA marker technologies and their applications in aquaculture genetics.

We constructed a genetic linkage map for a tetraploid derivative species, the rainbow trout (Oncorhynchus mykiss), using 191 microsatellite, 3 RAPD, 7 ESMP, and 7 allozyme markers in three backcross families. The linkage map consists of 29 linkage groups with potential arm displacements in the female map due to male-specific pseudolinkage arrangements. Synteny of duplicated microsatellite markers was used to identify and confirm some previously reported pseudolinkage arrangements based upon allozyme markers. Fifteen centromeric regions (20 chromosome arms) were identified with a half-tetrad analysis using gynogenetic diploids. Female map length is approximately 10 M, but this is a large underestimate as many genotyped segments remain unassigned at a LOD threshold of 3.0. Extreme differences in female:male map distances were observed (ratio F:M, 3.25:1). Females had much lower recombination rates (0.14:1) in telomeric regions than males, while recombination rates were much higher in females within regions proximal to the centromere (F:M, 10:1). Quadrivalent formations that appear almost exclusively in males are postulated to account for the observed differences.

https://www.genetics.org/content/genetics/155/3/1331.full.pdf

A Microsatellite Linkage Map of Rainbow Trout (Oncorhynchus mykiss) Characterized by Large Sex-Specific Differences in Recombination Rates

Microsatellites and their genomic distribution, evolution, function and applications : A review with special reference to fish genetics

The aim of this review was to highlight the extent to which the genetic technologies are implemented by the aquaculture industry. The review shows that some of the modern genetic technologies are already extensively applied by the diverse aquaculture industries, though not to the same extent for all important aquacultured species (according to FAO 1998 figures). Some species (common carp, Atlantic salmon, rainbow trout, channel catfish, Nile tilapia, and the Pacific oyster) received concentrated breeding efforts, while other major cultured species (Chinese and Indian carps and the giant tiger shrimp) received, so far, relatively limited attention, and a few species (Yesso scallop, blue mussel, white Amur bream, and milkfish) have, apparently, not been genetically improved at all. Most of the genetically improved strains reaching the aquaculture industry were developed through traditional selective breeding (selection, crossbreeding, and hybridization). Emerging, more modern technologies for genetic manipulation seem to take 10-20 years from being established experimentally until applications affect the industry. Thus, chromosome-set and sex manipulations started to affect the industry during the 1980's and 1990's. DNA marker technology and gene manipulations have yet hardly affected the industry. The former have not matured yet, but hold much promise. The latter could have affected the industry already had it not been restricted by public concern.

Genetic manipulations in aquaculture: a review of stock improvement by classical and modern technologies

Understanding how species and ecosystems respond to climate change has become a major focus of ecology and conservation biology. Modelling approaches provide important tools for making future projections, but current models of the climate-biosphere interface remain overly simplistic, undermining the credibility of projections. We identify five ways in which substantial advances could be made in the next few years: (i) improving the accessibility and efficiency of biodiversity monitoring data, (ii) quantifying the main determinants of the sensitivity of species to climate change, (iii) incorporating community dynamics into projections of biodiversity responses, (iv) accounting for the influence of evolutionary processes on the response of species to climate change, and (v) improving the biophysical rule sets that define functional groupings of species in global models.

Improving assessment and modelling of climate change impacts on global terrestrial biodiversity

We searched for linkage among 24 polymorphic loci (allozymes, RAPD, microsatellites) in three half-sib backcross families of rainbow trout (Oncorhynchus mykiss) produced by crossing strains divergent for the quantitative trait of upper temperature tolerance. Seven significant and two suggestive pairwise linkage associations between molecular marker loci were observed involving 14 loci clustered into four linkage groups. The association between a pair of allozyme loci (sIDHP-3* and mMEP-2 *) has been reported previously. Recombination rates varied greatly between the sexes and families. Two quantitative trait loci (QTL) were mapped by detecting a significant association between variance in upper temperature tolerance and alleles at the microsatellite loci Omy325UoG and Ssa14DU. The two QTL appear to reside in different linkage groups and account for ≈13 per cent and 9 per cent of the overall additive genetic variance in upper temperature tolerance. No significant interaction was detected between Omy325UoG and Ssa14DU suggesting that the effects of the QTL are additive.

/pdf/identification-of-two-qtl-influencing-upper-temperature-2kv104gr4c.pdf

Timothy R. Jackson

Papers

Identification of two QTL influencing upper temperature tolerance in three rainbow trout ( Oncorhynchus mykiss ) half-sib families

Epistasis in allelic expression at upper temperature tolerance QTL in rainbow trout