marker-assisted selection in wheat

334Marker-assisted selection – Current status and future perspectives in crops, livestock, forestry and fishTable 1Recently published linkage maps for various fish and shellfish species used in aquacultureSpeciesAtlanticsalmonRainbowtroutNumber ofmarkersMarkertypeMap lengthFemale/MaleMale Female ReferencecM(Kosambi)cM(Kosambi)473 AFLP 8.26:1 103 901 Moen et al., 2004a54 Microsatellites65 Microsatellites 3.92 np np Gilbey et al., 2004226 Microsatellites - 4 590 Nichols et al., 2003973 AFLP4 Allozymes72 VNTR29 Known genes12 Minisatellites5 RAPDs38 SINE*Oysters 115 Microsatellites 1.31:1 776 1 020 Houbert and Hedgecock, 2004Sea bass 174 Microsatellites 1.6:1 567.4 905.9 Chistiakov et al., 2005Kuruma 195 AFLP 1 780 1 026 Li et al., 2003prawnTilapia 525 Microsatellites 1:1 1 300 Lee et al., 200521 GenesScallops 503 AFLP 1.27:1 2 468 3 130 Wang et al., 2005Common 110 Microsatellites - 4 111 Sun and Liang, 2004carp105 Known genes57 RAPDsJapanese 111 Microsatellites 7.4:1 741.1 670.4 Coimbra et al., 2003flounder352 AFLPChannelcatfish313 Microsatellites 3.18:1 1 958 B Waldbieser et al., 2001B Sex-averaged* Short interspersed elementsnp = not publishedfunction of the transcript of genes (from anEST sequence) with the presence of a microsatellite,these markers are Type I markers(O’Brien, 1991; Serapion et al., 2004; Nget al., 2005). This strategy of developingmicrosatellite markers from known genesand ESTs has been used for common carp(Yue, Ho and Orban, 2004), rainbow trout(Rexroad et al., 2005; Coulibaly et al.,2005) and Atlantic salmon (Ng et al., 2005;Vasemägi, Nilsson and Primmer, 2005).In all these analyses, high levels oftransferability between populations andspecies can be expected if the microsatellitesare included in coding regions. Suchtransferability has been observed e.g.between Atlantic salmon and rainbow trout(Vasemägi et al., 2005; Rexroad et al., 2005),making these markers ideal for analyses ofpopulation genetics and comparative maps.For example, microsatellites derived fromEST sequences have been used to studydivergence of Atlantic salmon populationsin salt, brackish and freshwater habitats(Vasemägi, Nilsson and Primmer, 2005).Bioinformatic tools can be used forpotential discovery of SNPs using DNAsequence alignment “in silico” (Marth et al.,