Molecular Techniques for Genotyping

Genotyping is a process of determining the genetic constituent/genetic makeup “genotype” of an organism by examining the individual DNA sequence and comparing to a reference or other individual sequence. It helps the researchers to explore the genetic constitution, genetic linkages or variations like Single Nucleotide Polymorphisms (SNP) or multi-nucleotide changes in DNA. Identification of genotypes is also useful for determining their role in phenotypic expressions. Genotyping is an essential tool for researchers to find out disease-associated genes and gene variants. Genotype determined can also be used for the identification of susceptibility and prognosis for any disease and to find out responders/non-responders for a specific treatment, thus leading the way towards personalized medicine. Several molecular techniques have provided swift, reliable and accurate ways for determining genotypes. The process of genotyping involves molecular techniques like isolation and quantification of genomic DNA, visualization of DNA on agarose/polyacrylamide gel using electrophoresis, polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), random amplified polymorphic detection (RAPD) of genomic DNA, amplified fragment length polymorphism (AFLP), sequencing, allele-specific oligonucleotide (ASO) probes, microarrays etc. The present chapter will describe the protocols for different molecular techniques that are used to determine genotypes.

Keywords: CTAB, DNA isolation, Genomic DNA, Genotype, Oligonucleotide, Plants, Protocol, PCR, Polymorphism, Polymerase chain reaction, RAPD, RFLP, SNP.