DNA fingerprinting of Brassica juncea cultivars using microsatellite probes

Development and use of molecular markers: past and present

Molecular markers, due to their stability, cost-effectiveness and ease of use provide an immensely popular tool for a variety of applications including genome mapping, gene tagging, genetic diversity diversity, phylogenetic analysis and forensic investigations. In the last three decades, a number of molecular marker techniques have been developed and exploited worldwide in different systems. However, only a handful of these techniques, namely RFLPs, RAPDs, AFLPs, ISSRs, SSRs and SNPs have received global acceptance. A recent revolution in DNA sequencing techniques has taken the discovery and application of molecular markers to high-throughput and ultrahigh-throughput levels. Although, the choice of marker will obviously depend on the targeted use, microsatellites, SNPs and genotyping by sequencing (GBS) largely fulfill most of the user requirements. Further, modern transcriptomic and functional markers will lead the ventures onto high-density genetic map construction, identification of QTLs, breeding and conservation strategies in times to come in combination with other high throughput techniques. This review presents an overview of different marker technologies and their variants with a comparative account of their characteristic features and applications.

Evaluation of genetic diversity and genome fingerprinting ofPandorea(Bignoniaceae) by RAPD and inter-SSR PCR

Evaluation of the genetic relationship between five Pandorea jasminoides and eight Pandorea pandorana cultivars was investigated using random amplification of polymorphic DNA and inter-SSR (simple sequence repeat) PCR. Twenty-five random primers generated 375 polymorphic products with a mean number of 15 polymorphic bands per primer. The mean number of polymorphic products obtained by inter-SSR PCR was 18.7 per primer. Random amplification of polymorphic DNA and inter-SSR amplification of genomic DNA revealed higher genetic variability among the cultivars of P. pandorana than among those of P. jasminoides. Two random primers each produced species-specific amplification products in both the Pandorea species, while four random primers and two SSRs produced species-specific amplification products in only one of the species. A distinct cultivar-specific DNA fingerprint for each of the 13 cultivars was obtained by 2 random primers and 1 SSR primer. A dendrogram constructed on the basis of 513 amplification products generated by random amplification of polymorphic DNA and inter-SSR PCR showed the separation of 13 cultivars into two major groups that corresponded to P. jasminoides and P. pandorana. The data resulting from random amplification of polymorphic DNA and inter-SSR PCR were congruent. Our study showed that it should be possible to take advantage of existing genetic variability of P. pandorana to enhance the narrow genetic base of P. jasminoides by interspecific crosses. Such crosses would have the potential to generate novel commercially important elite cultivars of Pandorea.Key words: Pandorea, RAPD, inter-SSR, DNA fingerprint, genetic variability.