Abstract
As a codominant genetic marker, restriction fragment length polymorphism (RFLP) has been widely applied to the prenatal diagnosis of some genetic diseases. To evaluate the usefulness of the genetic markers in prenatal diagnosis, a parameter, the diagnosable rate or the proportion of diagnosable matings, is estimated when two or more genetic markers are used. The assessment is based on the distribution of haplotypes.
By using the data of the distribution of haplotypes of β-A (normal) and β-T (β-thalassemia) chromosomes in a Chinese population and the formula given, it is easy to calculate the different diagnosable rates of all the combinations of seven given genetic markers. The results could help us to find an appropriate combination of genetic markers in prenatal diagnosis and, therefore, makes it possible to obtain a sufficiently high diagnosable value with a limited number of genetic markers.