We can observe a phenotype whether or not we understand the genetics behind it. In real life, there is a gene called HERC2 that works like I described, and most people with blue eyes have the broken allele of this gene.
Nerves, Neuroglia, and Ganglia. A nerve is a bundle of fibres (axons and/or dendrites) outside the CNS. Neuroglia are cells of the nervous system that help protect and support it. Ganglia are groups of nerve cell bodies lying outside the CNS.
Full Definition of NERVE. 1. 2. : any of the filamentous bands of nervous tissue that connect parts of the nervous system with the other organs, conduct nerve impulses, and are made up of axons and dendrites together with protective and supportive structures. 3.