Final answer:
Anatomical differences between humans and apes, despite their shared genetic material, are attributed to variations in regulatory genes that affect gene expression and developmental processes.
Step-by-step explanation:
Given that humans and apes share over 98 percent of their genetic material, their anatomical differences are likely due to differences in regulatory genes. These regulatory genes play a vital role in the expression and timing of other genes, leading to the distinct anatomical traits seen in humans and apes despite the high percentage of shared DNA. Small changes in these genes can have significant effects on an organism's development and physical appearance.
For instance, the inversion of a chromosome segment in the human lineage has repositioned genes like ROCK1 and USP14 and possibly reset their expression levels, potentially contributing to some key differences between humans and other apes. This is just one example of how structural changes in the genome can lead to divergence despite a high degree of genetic similarity.
Overall, the genetic similarities suggest a close evolutionary relationship, but the specific changes in regulatory regions are responsible for the unique characteristics distinguishing each species.