A recent study from the University of Leipzig, just published, open access, in Molecular Psychiatry highlights the difference between an intelligently designed system and one which evolved naturally. Change a single gene involved in neurotransmission and the human feature that creationists wave as evidence for intelligent design - the human brain - seriously malfunctions.
The gene, GRIN2A, encodes a key subunit of the NMDA receptor — a molecular gateway through the cell membrane of neurones essential for learning, memory, language development, and the ability of the brain to fine-tune its own wiring. When functioning normally, children learn to speak, form memories, and develop the balanced neural circuits that underpin thought and behaviour. When it doesn’t, the result can be epileptic seizures, speech loss, cognitive impairment, and an increased vulnerability to psychiatric illness. In some cases, even sleep becomes a time of neurological storm activity, with continuous spike-wave patterns eroding normal brain development.
For anyone who understands evolution, this fragility makes perfect sense. For those insisting that the human brain is the product of foresight and planning, it presents a serious problem. It is a system built by evolutionary tinkering, not design. The NMDA receptor is one of the pillars of excitatory communication in the brain. Yet it is also a precarious, expensive and failure-prone piece of biological machinery. A single amino acid substitution in the GRIN2A protein can derail synaptic signalling, scramble brain rhythms, or impair the processes that enable children to acquire language.
This is not what robust design looks like.
