Previous Page
Next Page

Frequency Primer

Let's Review:

Sam Wasser and colleagues use 16 markers to identify elephants. Using this many markers makes an identification almost certain and, as you will learn in Case Two, allows scientists to determine where in Africa an ivory sample came from, even in the absence of a DNA sample from a poached elephant.

The gel at left (see below) shows the genotype of an ivory sample that was analyzed using all 16 markers.

Using the allele frequencies listed, what is the chance that an elephant other than the one sampled from Garamba National Park would have this genetic profile?

Try again. You know that with four markers the probability that an individual has the genetic profile of the ivory sample is 1 in about 90 million. With 16 markers, the probability will be much smaller.

Correct. By multiplying the frequencies for each marker you should have determined that the probability that an elephant would have this genetic profile is 6.72 x 10-25 or 1 in 1.5 x1024.

Next Page