Microsatellites of Laminaria digitata tested in Lessonia nigrescens: Evaluation and improvement of cross amplification between kelps of two different families

Abstract

The use of primers designed originally to amplify DNA for one species in a different one can save time and resources, particularly for microsatellite loci. Microsatellite amplification improvements across two kelp families are reported, where loci originally described in Laminaria digitata (Laminariaceae) were tested in Lessonia nigrescens (Lessoniaceae). Amplification tests of 15 loci were successful for 12 cases. However, 11 of them presented multilocus banding profiles and only 1 was monolocus, but far from the expected size range. In addition, single primer PCRs using 25 forward or reverse primers gave again 12 multilocus profiles, indicating various mutational steps between both species. Sequenced PCR products for two loci revealed additional mutations in microsatellites and flanking regions. PCR products were improved by designing new primers or by "Touchdown" PCR. Polymorphism test in L. nigrescens for improved locus Ld2/167 gave six alleles in fifty-two genes with expected heterozygosity, H e = 0.686 and observed heterozygosity, H o = 0.384. A much lower H o 's (H o ≤ 0.25) was observed in two localities affected by massive mortality events. Nei's distances among five populations presented similar patterns to those of 30 multilocus dominant loci (RAPD) evaluated in the same localities. Although some success might be achieved in cross-species microsatellite amplifications, the strong mutations detected between these two Laminarian families suggests that better results of cross-amplifications should be expected at much lower taxonomic levels. Thus, although more expensive, construction of new gene libraries is strongly recommended.

Development and utility of EST-SSR markers in Ulva prolifera of the South Yellow Sea

“…The previous reports shows that the transferability of EST-SSRs from one species to another ranges from 40% to 89% (Liang et al, 2009). For seaweeds, the study of microsatellite cross-amplification between similar species has been reported in brown seaweeds and red seaweeds (Engel et al, 2003;Martínez et al, 2005).…”

“…At present, SSRs have been utilized in genetic diversity analysis of seaweeds like red algae and brown algae (Kusumo et al, 2004;Martínez et al, 2005;Sun et al, 2006;Xie et al, 2009;Wang et al, 2011). However, little information is available regarding genetic variation of Ulva bloom algae with SSR markers to date except for Ulva intestinalis (Alström-Rapaport and Leskinen, 2002;Kostamo et al, 2008).…”