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.
