Microsatellite marker has many advantages such as a great quantity, extensive dispersion around the genome, high polyomorphism, Mendelian codominant inheritance, rapid and convenient detection.
Now if you know anything about genetics you know that simple Mendelian genetics, it looks like purple is dominant and white is recessive but we know that because of the work of Mendel.
That's a pretty simplified version but I hope you get the picture and let me know if you want me to explain chromosomes and Mendelian genetics sometime on another episode. I love this stuff.