ABSTRACT
One of the characteristics of mammals is the presence of hair. Hair has evolved along with each mammal such that characteristics can be species specific. It is important to be able to recognize the different types of hairs within the species being studied since experimental protocols or mutations can affect one type and not another. Mutations, both spontaneous and iatrogenic, occur in all species. This chapter tabulates mouse mutations with defects (missing or abnormal morphology) of specific hair types. The mouse has eight major hair types, based upon their anatomical location and distinct morphological features at the gross and microscopic levels and the presence or absence of these particular hairs in various mutations. These include the pelage or truncal hairs, vibrissae (tactile hairs, sensory hairs, whiskers), cilia (eyelashes), tail hairs, ear hairs, and hairs around the feet, nipples, and perianal/genital regions. The pelage hairs have been studied extensively in the mouse, almost to the exclusion of all others.
