Integument supplement

Integument supplement - to produce melanin in areas that...

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APC 100-Integement Lectures: Additional class questions FYI 1. What type of glands constitute the paired anal sacs in dogs? Anal sacs are paired cutaneous diverticula with ducts that open up into the anal canal; the ducts and lumen are lined with stratified squamous epithelium. In the dog, apocrine glands empty their product into the lumen of the anal sac. In cats, the both sebaceous and apocrine glands empty into the lumen of the anal sac. 2. A student asked about a mutation that results in markings associated with Siamese cats. This marking pattern is a type of albinism that is associated with deficient synthesis of melanin pigment due to abnormal activity of tyrosinase (involved in melanin biosynthesis pathway). Because of a mutation in the tyrosinase gene, the enzyme becomes temperature sensitive and only functions
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Unformatted text preview: to produce melanin in areas that areas with lower body temperature (extremities). A homologue of this mutation is also observed in the Himalayan mouse and in humans. 3. What causes variations in hair types? At a very basic level, we talked about how organization of keratinocytes in the hair shaft can result in some variations. But, hair types are clearly more complex and depend upon variations in specific proteins to generate multiple phenotypes. Take a look at this study published in the journal Science last year, which identified variations in three different genes that contribute to hair type in 80 different dog breeds (Cadieu, et. al. Science 326 , 150 (2009)). Below is a summary table of the three genes, one is a type of keratin:...
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