Reasons to Believe

New Brain Study Spoils Evolutionary Drama

Othello:
But this denoted a foregone conclusion.
Iago:
‘Tis a shrewd doubt, though it be but a dream,
And this may help to thicken other proofs,
That do demonstrate thinly.
          Othello Act 3, scene 3

A few years ago, I attended a rather provocative production of Shakespeare’s Othello at a nearby college. Although the performers stuck to the original script, they wore modern military garb. A few months later I saw Othello performed in London at the Globe Theater. It was a “bucket list” experience for me and as close as anyone could come to viewing Othello as first presented to audiences in England.

I thoroughly enjoyed both performances, yet the two productions created a very different experience: same script, different presentations.

Genetic comparisons between humans and chimpanzees are like the dual versions of Othello. These two species harbor virtually the same genetic information, but that information presents itself in different ways. And, as it turns out, this relatively recent recognition challenges one of the most pervasive icons of evolution—the “genetic similarity” between humans and chimpanzees.

For many, the 99% sequence overlap observed for proteins and DNA indicates that humans and chimpanzees descended from a common ancestor in the not-too-distant past. Accordingly, the small genetic differences arose as a consequence of mutational changes after the human and chimpanzee lineages split.

Although many evolutionary biologists consider the genetic closeness as profound, it really is a largely meaningless comparison. Similar genetic makeup doesn’t explain why such fundamental biological and behavioral differences exist between us and these creatures.

Scientists have recently learned that these dramatic differences stem largely from gene expression patterns in the human and chimpanzee brains. (Gene expression refers to the overall gene activity of the cells comprising a specific tissue, organ, etc. Gene expression can be thought of as an inventory of the genes that are “turned on”—directing the production of proteins—and the genes that are “turned off.” It also describes the quantity of different proteins produced as a result of gene activity.)

New work by researchers from the United States and Norway adds to our understanding of this difference.1 Investigators demonstrated differential activity of proteins called transcription factors in human and chimpanzee brains. These proteins interact with DNA, controlling gene expression. The transcription factors that showed the greatest differences were of two types: those involved with (1) nerve cell growth and protection, and transmission of signals between nerve cells; and (2) energy metabolism (increased brain activity demands more energy).

Such research demonstrates meaningful and significant genetic differences between humans and apes—not in the gene sequences, but in how the genes are used. And this gene usage dramatically impacts brain structures.

The genetic similarity between humans and chimpanzees does not controvert a biblical view of human origins. In fact, Scripture seems to imply that biological similarity exists between humans and other animals, including the great apes. Although many scientists take evolution as a “foregone conclusion,” this study helps to “thicken other proofs” of the veracity of a biblical account of human origins.

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1 Katja Nowick et al., “Differences in Human and Chimpanzee Gene Expression Patterns Define an Evolving Network of Transcription Factors in Brain,” Proceedings of the National Academy of Sciences, USA 106 (2009): 22358-22363.

Subjects: Humans vs. Chimps

Dr. Fazale Rana

In 1999, I left my position in R&D at a Fortune 500 company to join Reasons to Believe because I felt the most important thing I could do as a scientist is to communicate to skeptics and believers alike the powerful scientific evidence—evidence that is being uncovered day after day—for God’s existence and the reliability of Scripture. Read more about Dr. Fazale Rana