If you have any questions about double merles or genetics you can e-mail me. I love to get e-mail and will have my humans check it for me so I can help them write a response to you quickly.

Or, if you want more scientific detail on hearing and sight development keep reading, like maybe those of you who are students working on a research paper.

In order to fully understand why a double merle can be deaf due to lack of white pigment in the inner ear, we need to understand the basics of how sound is transmitted from the ear to the brain stem. The ear consists of three parts: The external ear, the middle ear and the inner ear. Sound enters through the external ear opening as air vibrations which are funneled through the ear canal. The eardrum then vibrates and transmits the energy of the sound waves to the middle ear. The "bones" of the middle ear, or the hammer, anvil and stirrup act as transformers and convert the vibrations which are then transmitted to the inner ear.

The inner ear consists of three segments: cochlea, vestibule and semicircular canals. The cochlea is coiled like a snail's shell and is filled with fluid. Within the cochlea is the organ of Corti that contains hair cells which act as receptors. The hair cells convert the mechanical energy to electrical nerve energy which then passes along the cochlear nerve and through the network of nerves to the brain stem.

The inner ear is where the lack of pigment comes into play in causing deafness. In order for the hair cell to convert the mechanical energy into electrical or nervous energy, the hair cell must contain a pigment cell, if it doesn’t the hair cell cannot convert the mechanical energy and the ‘sound’ ends before reaching the brain stem.