Use of synthetic probes.
If protein, purified using the technique of two dimensional gel electrophoresis, is used for microsequencing of 5-15 consecutive amino acids, this information can be used for the synthesis of oligonucleotides (using automated DNA synthesizers). These oligonucleotides may then be directly utilized for screening of cDNA or genomic libraries for isolation of specific genes (Fig. 8.3) These can also be used for designing primers for the amplification of a gene in extracted from a tissue. A 32 kilodalton (kD) glycoprotein (isolated from style) associated with the S2 incompatibility allele of Nicotiana allata was used for synthesis of an oligonucleotide leading to the isolation of a related gene



