1. BIOLOGY 12
Multiple Alleles

2. Multiple Alleles
it is possible to have more than two different alleles for one gene
can only have two alleles at one time, but there are more than two possibilities

3. Multiple Alleles
no longer appropriate to use uppercase and lowercase letters
use capital letters to indicate gene
use number or letter superscripts to indicate allele

4. Fruit Flies example
the study of Drosophila melanogaster (fruit flies) has proved this
eye colour possibilities:
red (or wild)
apricot
honey
white

5. Fruit Flies Example fruit fly eye colour shows a dominance hierarchy:
wild type is dominant over apricot
which is dominant over honey
which is dominant over white

7. Example
What is the phenotypic ratio of the offspring from the mating of the following two fruit flies? x

8. Example

9. Practice
determine the possible phenotypes of a cross between a fruit fly with pure honey eyes and a fly with wild eyes with the white allele