Genetic characterization of cassava (Manihot esculenta) landraces in Brazil assessed with simple sequence repeats

Based on nine microsatellite loci, the aim of this study was to appraise the genetic diversity of 42 cassava (Manihot esculenta) landraces from selected regions in Brazil, and examine how this variety is distributed according to origin in several municipalities in the states of Minas Gerais, São Paulo, Mato Grosso do Sul, Amazonas and Mato Grosso. High diversity values were found among the five above-mentioned regions, with 3.3 alleles per locus on an average, a high percentage of polymorphic loci varying from 88.8% to 100%, an average of 0.265 for observed heterozygosity and 0.570 for gene diversity. Most genetic diversity was concentrated within the regions themselves (HS = 0.52). Cluster analysis and principal component based scatter plotting showed greater similarity among landraces from São Paulo, Mato Grosso do Sul and Amazonas, whereas those from Minas Gerais were clustered into a sub-group within this group. The plants from Mato Grosso, mostly collected in the municipality of General Carneiro, provided the highest differentiation. The migration of human populations is one among the possible reasons for this closer resemblance or greater disparity among plants from the various regions

DNA fingerprinting using arbitrary primer technology (APT): A tool or a torment

A recent variation of the PCR has allowed DNA fingerprints to be obtained independently of prior sequence information and with unparalleled ease. Several approaches, conveniently grouped under the general term of arbitrary primer technology (APT), include the popular RAPD, DAF, and AP-PCR methods. A great deal of attention has been focussed on these methods and questions have arisen regarding reproducibility, DNA fingerprint resolution, and even the future of the technology itself. Here we discuss these issues and examine some of the unique properties of DNA amplification using a single short arbitrary primer