Mette Serine Wesmajervi

Identification and characterisation of thirteen new microsatellites for Atlantic cod (Gadus morhua L.) from a repeat-enriched library

A total of 13 polymorphic microsatellite markers were developed for Atlantic cod (Gadus morhua L.) from a repeat-enriched library. Polymorphism of each locus was assessed in 96 unrelated individuals from a natural population. The number of alleles per locus varied from 8 to 45. The ranges of observed and expected heterozygosity were 0.122–0.907 and 0.673–0.965, respectively. Four of the loci (Gmo-G24, Gmo-G40, Gmo-G46 and Gmo-G49) followed Hardy–Weinberg expectation. No evidence for linkage disequilibrium between pairs of loci was found in any combination of loci pairs, except between Gmo-G40 and Gmo-G43. These microsatellite markers provide useful tools for studies of population genetics, reproductive ecology and for constructing linkage maps of Atlantic cod.

Development of ten new EST-derived microsatellites in Atlantic cod (Gadus morhua L.)

Ten polymorphic microsatellite markers were developed from approximately 1,300 expressed sequence tags (ESTs) of Atlantic cod (Gadus morhua L.). Thirty two primer pairs were designed for EST sequences containing perfect di- tri- tetra- and pentanucleotide motifs and characterised in 96 unrelated fish. Ten markers were successfully amplified with number of alleles from 2 to 13 per locus and observed and expected heterozygosity ranging from 0.03 to 0.69 and 0.03 to 0.74, respectively. Loci Gmo-C131, C132 and C136 deviated from Hardy-Weinberg equilibrium. Genetic linkage disequilibrium analysis between all pairs of the loci showed significant departure from the null hypothesis between loci Gmo-C131 and Gmo-C132 and C128 and Gmo-C133. The gene identity was determined at five of the loci, confirming the associated microsatellites as Type I markers. The new microsatellites reported in this work can be used for conservation and enhancement of wild stocks for commercial harvesting.

Identification and characterisation of nine new gene-associated microsatellite markers for Atlantic cod (Gadus morhua L.)

Nine polymorphic microsatellite markers were identified by screening of 2464 ESTs derived from a cDNA library of Atlantic cod (Gadus morhua L.). About 35 novel microsatellite loci were selected and characterised in 96 individual cod. Nine markers were successfully amplified with number of alleles from 3 to 18 per locus and the average heterozygosity was 0.57 in the panel examined (range 0.29–0.86). All loci followed the Hardy–Weinberg expectation and no significant linkage disequilibrium was found in a test including all pairwise combinations. The gene identity was determined at four of the loci, confirming the associated microsatellites as Type I markers.

Development of twenty sequence-tagged microsatellites for the Atlantic cod (Gadus morhua L.)

Fifty-four primer pairs were designed for expressed sequence tag (EST) sequences containing perfect di- and tri-nucleotide motifs and characterised in 96 unrelated fish. Twenty markers were successfully amplified with number of alleles from 2 to 10 per locus and observed and expected heterozygosity ranging from 0.01 to 0.56 and 0.03 to 0.70, respectively. Loci Gmo-C213, Gmo-C246 and Gmo-C247 deviated from Hardy–Weinberg equilibrium. Genetic linkage disequilibrium analysis between all pairs of the loci showed significant departure from the null hypothesis between loci Gmo-C213 and Gmo-C222, Gmo-C233 and Gmo-C229, C223 and Gmo-C236 and C229 and Gmo-C236. The gene identity was determined at 10 of the loci, confirming the associated microsatellites as Type I markers. These microsatellite markers provide useful tools for studies of population genetics, reproductive ecology and constructing linkage maps of Atlantic cod.

New polymorphic di-nucleotide microsatellite markers for Atlantic cod (Gadus morhua L.)

Twenty three polymorphic microsatellite markers were developed from approximately 2,300 expressed sequence tags (ESTs) of Atlantic cod (Gadus morhua L.). Seventy two primer pairs were designed for EST sequences containing perfect di-nucleotide motifs and characterised in 96 unrelated fish. Twenty three markers were successfully amplified with number of alleles from 2 to 18 per locus and observed and expected heterozygosity ranging from 0.03 to 1.00 and 0.04 to 0.90, respectively. Loci Gmo-C280, Gmo-C283, Gmo-C290 and Gmo-C293 deviated from Hardy–Weinberg equilibrium. Genetic linkage disequilibrium analysis between all pairs of the loci showed significant departure from the null hypothesis between loci Gmo-C267 and Gmo-C269 and Gmo-C262 and Gmo-C291. The gene identity was determined at three of the loci, confirming the associated microsatellites as Type I markers. These microsatellite markers provide useful tools for studies of population genetics, reproductive ecology and constructing linkage maps of Atlantic cod.