The high concentration of amplified DNA allows us to see the marker as a band in the electrophoresis gel. 2 Resemblance of placoderms and agnathans with wild-type and mutant zebrafish embryos lacking a jaw. RAPD markers can be used in two different kinds of analysis. This technique allows us to test several markers for possible linkage to the mutation in a short period of time. 3 Photograph of an electrophoresis gel.
Vertical lanes represent the genome of individual embryos.
First, they have has been stained with ethidium bromide, an intercalating agent, which binds between the two strands of DNA and fluoresces when irradiated with UV light. The fact that each embryo has different markers in its genome accounts for the genetic differences between individuals. Normally, screening markers amplified by 300 randomly chosen primers using BSA yields about 5-10 putative markers. Putative markers have high probabilities of being linked to the mutation. RAPD assays of these few markers will tell us if the marker is, in fact, linked to the mutation and give us the genetic distance.