ABSTRACT
The soft coat mutation arose spontaneously at the Jackson Laboratory. All four pelage hair types are present in soc/soc mice; however, they are thinner than normal with occasional irregularities in thickness along the length of the shaft. Histologic evaluation of skin sections revealed that at birth, soc/soc epidermis consisted of a clearly defined basal cell layer covered by three or four distinct layers of flattened, interdigitating cells. Within the bulb of the soc/soc hair follicle, pigment-laden melanocytes form a rough semicircle around the dermal papilla. Trigg described abnormalities in the bulb region that could account for the abnormal hairs formed in the soft coat mouse mutation. Many of the mouse mutations described in this monograph that present with alopecia or abnormal hair coats are due to structural abnormalities of the hair shaft and may be similar to the soft coat mutation. The soft coat mutation is not commonly used in biomedical research.
