RFLP and Genetic Screening
Linked DNA Markers
The following illustration shows the relationship between two markers and a gene.
1 cM Gene Marker 1 | | ___________________________________________Marker 2
5 cM Gene Marker 2 | | ___________________________________________Recombination is less likely to occur between marker 1 and the gene than between marker 2 and the gene. Actually there is only a 1% chance the linkage between marker 1 and the gene will be broken. For diagnostic purposes 99% of the time the individual with marker 1 will have the specific allele of the gene of interest. Marker 2 is 95% accurate in diagnosing the specific allele at the gene of interest. Obviously, the closer the marker is to the gene the more accurate the testing procedure. But the best probe still is one that actually hybridizes to the particular gene that is in question. Copyright © 1997. Phillip McClean