Holstein cattle are normally black and white. A su- perb black and white bull, Charlie, was purchased by a farmer for $100,000. All the progeny sired by Charlie were normal in appearance. However, cer- tain pairs of his progeny, when interbred, produced red and white progeny at a frequency of about 25 percent. Charlie was soon removed from the stud lists of the Holstein breeders. Use symbols to ex- plain precisely why.

Sally, age 3 months, has a moist, red, vesicular rash on her cheeks, the backs of her hands, and her arms. her mother said sally was constantly trying to scratch the rash and often has difficulty sleeping. her father has a family history of allergic rhinitis and asthma. discussion questions. 1. review atrophic dermatitis from chapter 3 and discuss the pathophysiology of sally’s symptoms. 2. why is the father’s medical history significant, and what can sally expect as she grows up? 3. discuss the need to limit scratching, and describe practical methods to achieve this.