Single feature polymorphism array 16K Unigenes: marker discovery in melon

One of the methods used to search for molecular markers is DNA hybridization to microarrays. Microarray hybridization of DNA from different individuals can reveal differences between them (single-feature polymorphisms (SFPs)). These SFPs can be used as markers for breeding purposes, or they can be converted to conventional markers by sequencing. This method has been utilized in a few different plants to discover genetic variation using Affymetrix arrays that exist for only a few organisms. We applied this approach, with some modifications, for marker discovery in melon. For marker discovery, we used DNA from the parents of our mapping population, developed by Katzir's group from a cross between representatives of two subspecies of Cucumis melo L.: PI414723 (subspecies agrestis) and 'Dulce' (subspecies melo). Two biological replicates from PI414723 and two from 'Dulce' were used. Each biological replicate contained gDNAs pooled from 10 different plants. gDNA samples were labeled and hybridized using standard Agilent procedures for comparative genomic hybridization (CGH). The inter-population genetic variation was detected using two arrays, with one of the biological replicates of 'Dulce' against one of the PI414723 replicates on each array. The intra-population variation was detected by hybridizing the PI414723 replicates against each other and the 'Dulce' replicates against each other. Intra-population variation was estimated to ensure that the genetic variation between these populations is based on alleles that are fixed in the population and not due to intra-population variation.