Genetic analysis of heterozygous loci using serial single-strand conformational polymorphism analysis

The detection of genetic polymorphisms is becoming increasingly important and so new methods that promote fast and efficient analysis will become necessary. In many cases, we can find individuals who are homozygous for different alleles. Evaluating the DNA sequences of these alleles is straightforward, for instance, by direct sequencing of an amplified PCR product. However, if we are looking for very rare or lethal alleles and, as a consequence, there is only a very low or even no chance of finding homozygous individuals for investigation, we have to use heterozygous individuals for genetic analysis. To avoid artefacts from direct DNA sequencing of heterozygous genomes¹, the two alleles must be split by cloning them into a vector so that each allele can be investigated separately. To be certain of finding both alleles, a number of time-consuming sequencing runs must be performed. Here, we present a simple way to screen colonies of interest.