In pea plants, Mendel observed several traits that had two alleles. However, not all traits exhibit this pattern of inheritance. In the Mongolian gerbil, there is a gene that controls the balance of black and yellow within the fur. The first version of the allele, E, causes fur to have a dark base and black tips, with yellow in the middle. A mutation causes the, e allele, which decreases the amount of black in the fur and results in a lighter appearance. There is also a third version, ef, which causes fading of all the black pigment, resulting in a very light-yellow coat. Mongolian gerbil with fading of all the black pigment, causing a very light yellow coat.

Part 1: Based on the information provided, what can you conclude about the pattern of inheritance for this gene?
Part 2: How would gerbil colors be different if there were two alleles, as Mendel noted in pea plants? Explain how this is different from what is observed.