The Sand Hills of Nebraska are a relatively recent geological formation with an age of approximately 10 000 to 15 000 years old Because of quartz crystals in the sand the Sand Hills are lighter in color than the surrounding area Deer mice Peromyscus maniculatus inhabit much of the Midwest and have a dark brown coat color However at the Sand Hills where the sand is lighter the Deer Mice have a lighter golden coat In other words the mice on the Hills have a coat color that blends in with the sand The main predators of these mice are birds and it is thought that blending in with the background increases the mice s likelihood of survival Scientists have identified a single gene Agouti which is responsible for the differences in coat color Linnen et al 2009 Below are partial DNA nucleotide sequences from the coding region of the Agouti gene which codes for the protein that affects coat color These sequences were obtained from five mice from five different deer mouse populations Mice A B and C come from regions other than the Sand Hills whereas Mice D and E come from the Sand Hills Mouse A dark Mouse B dark Mouse dark Mouse D light Mouse E light AGG CCT TGC TCA AAA GTA TCG CGC TAG AGG CCT TGC TCA AAA GTA TCG CGC TAG AGG CCT TGC TCA AAA GTA TCG CGC TAG AGG CCT TGC TCA GTA TCG CGC TAG AGG CCT TGC TCA GTA TCG CGC TAG Using a technique called mutation analysis the new Sand Hills Agouti allele gene variant in mouse D and mouse E is estimated to be around 8 000 years old That means the lighter coat color appeared after the formation of the Sand Hills How would a biologist best explain the reason for the appearance of the allele One mouse living in the Sand Hills randomly obtained the lighter coat color mutation and produced lighter coat colored offspring Because they survived more than the darker colored mice all the lighter coat colored mice are descendants of the original mouse O The dark coat color gene mutated into the light coat color gene because the mouse was exposed to the lighter colored sand O A group of mice came to the Sand Hills and the dark coat color gene mutated because the mice needed to blend in with the sand to avoid being eaten by birds