If Human and Chimp DNA Are So Similar, Why Are There So Many Physical and Mental Differences Between Them?

When studying the human genome and its similarity to that of the chimp, scientists have recently concluded that 96% of our genome is similar. However, most people are unaware that this percent pertains to the regions of our DNA that result in proteins. It seems logical that if a protein performs a certain function in one organism, then that same protein should perform the same function in a variety of organisms. This is evidence for a common designer as much as for a common ancestor. But most of the DNA sequence performs an unknown function and has been largely dismissed as “junk DNA.” However, increasing evidence supports the view that “junk” DNA performs an important role. For example, a recent report unexpectedly found specific sequence patterns in “junk” DNA which scientists have termed “pyknons.”1 It has been suggested that these pyknons may be important in determining when and where proteins are made.

Within this “junk DNA” there may be large differences between man and chimp. The areas of greatest difference appear to involve regions which are structurally different (commonly called “rearrangements”) and areas of heterochromatin (tightly packed DNA).

Here are some other interesting differences between the human and chimp genomes which are often not reported:

• The amount of chimp DNA is 12% larger than what it is in humans.
• Several hundred million bases (individual components of the DNA) of the chimp genome are still unanalyzed.
• In many areas of the DNA sequence, major “rearrangements” seem apparent. These account for perhaps 4–10% dissimilarity between chimps and humans.
• Chimps have 23 chromosomes and humans have only 22 (excluding sex chromosomes for both species).

Thus, the physical and mental differences between humans and chimps are most likely due to the differences in purpose and function of the so-called junk DNA. This understanding should leave us more mindful of the awesome complexity of the Creator and His creation of DNA.

Dr. Georgia Purdom earned her doctorate from Ohio State University in molecular genetics and spent six years as a professor of biology at Mt. Vernon Nazarene University. Dr. Purdom is also a member of the American Society for Microbiology and American Society for Cell Biology.