Genetic

Genetic fingerprinting is one of the DNA-based techniques that have permeated a wide gamut of biological research, beginning with forensic biology and medicine and now ex-tending to agriculture. The advent of polymerase chain re-action (PCR) ushered a revolutionary approach in producing genetic fingerprints, supplanting hybridization-based techniques. PCR-based methods can be accomplished using either arbitrary markers of un-known location in the genome or those markers that target specific genome sites. Among agricultural crops, rice and maize are the most intensively characterized for DNA markers. At present, genetic finger-printing has also been applied in many aspects of crop biology, such as taxonomy and phylogeny, diversity analysis, hybridity testing, gene mapping, molecular breeding, and somaclonal variation. This paper describes genetic fingerprinting technology and discusses its applica-tions in the major crops of the Philippines, highlighting the progress made by Filipino scientists. Discovery and principle of genetic fingerprinting The past century marked groundbreaking discoveries in the biological sciences particularly in the area of molecular biology. Since the discov-ery of the DNA structure in 1953, researchers have been increasingly empowered to analyze and manipulate genetics using the principles of nucleic acid biochemistry. The beginnings of DNA profiling or genetic fingerprinting can be traced in the work of geneticist Alec J. Jeffreys of the University of Leicester in Great Britain, on the gene for myoglo-bin, a protein that stores oxygen in muscle cells (Jeffreys et al., 1985). He found that the myoglobin gene contains many segments that vary in size and composition from individual to individual and that have no apparent function. Jeffreys called these segments minisatellites be-cause they are small and are located near the gene that actually serves as a genetic blueprint. Minisatellites are tandemly arranged, repetitive DNA elements scattered throughout eukaryote and prokaryote ge-nomes, the short basic units of which are mostly imperfectly reiterated at each locus (Epplen et al., 2005). Minisatellites comprise 10 – 100 nucleotide-long repeat units