ABSTRACT
The study of gene structure and DNA polymorphism has been greatly facilitated with the use of non-isotopic probes and polymerase chain reaction. The latter involving amplification, yields sufficient amount of DNA for electrophoresis. Polymorphism in genes is ultimately resolved through hybridization with probes. In horizontal gene transfer, it is necessary to have a clear understanding of the localization, site of expression and the product of gene expression, before isolation. A different strategy for isolation and localization of genes in the wheat and its allies with large genomes has been suggested. This strategy is based on the premise that most cereals are derived from a common genome as evidenced. On the basis of a conserved marker synteny, and a set of homoeologous probes, the colinearity of the three wheat genomes has been established. The genome colinearity shows the conservation of the gene order in wheat, rice and maize, despite evolutionary diversification through 50 million years.
