Excerpted from Patricia’s talk “Exploring the Uniqueness of Human Embryology.”
Sometimes, as Christians, we may feel embattled and almost overwhelmed by our secular culture’s low view of humanity—the outcome of a purely naturalistic framework. However, I like to remind people that many scientists have devoted themselves to understanding the biological uniqueness of humans. In order to achieve the goals of their research, such as curing and preventing diseases, they work to understand not what makes us similar to chimps (and other creatures), but what makes us different.
Humanity’s uniqueness is evident at all levels of our biology, as demonstrated by various features of brain development.
- The Organism Level
- Humans experience prolonged (compared to other species) periods of both in utero and postnatal brain development.
- The Macroscopic Level
- The human cerebrum is 10 times larger than the chimp’s.
- The human cerebrum contains many more neurons and connections between neurons than any other species.
- The Microscopic Level
- The human brain possesses types of neurons unique to our species.
- Predecessor neurons—the first neurons in the human brain—form earlier in development than embryologists originally thought possible.
- The Genomic Level
- The developing brain expresses 76 percent of all its genes. No other species expresses so much of its genome in one tissue.
- The developing human brain tailors gene expression in a species-specific way:
- 33 percent of the genes are expressed to varying extents in different regions of the brain, creating a unique dose-dependent pattern.
- 28 percent of the genes are alternatively spliced, resulting in the production of a different protein.
- 17 percent of the genes are expressed in both a regionally distinct pattern and alternative splicing form.
- The Molecular Level
- The human genome contains multiple sequences that differ dramatically from comparable chimp sequences.
- Regions of dramatic difference are called HARs (human accelerated regions) because they contain more sequence dissimilarities from the chimp sequence than the evolutionary paradigm would predict.
Each year’s advancing research reveals more, not fewer, ways in which human biological systems, organs, and tissues differ from those of other creatures.
Dr. Patricia Fanning
Patricia Fanning is an RNA biochemist with a PhD from North Carolina State University and formerly a consultant for software companies. As a visiting scholar to Reasons To Believe in 2011, she specialized in human embryology and evolutionary development and regularly contributed to RTB’s podcasts and publications.