Answer the following about the developmental biology behind your Dalmatian’s health problems, for 10 points each.
[10m] Many Dalmatians are deaf because mutations in MITF (“mit-f”) kill these cells as they migrate to the skin and ear. These ectodermal stem cells undergo an epithelial-mesenchymal transition atop a namesake “tube.”
ANSWER: neural crest cells [prompt on neural stem cells; prompt on melanocytes by asking “what stem cells are melanocytes derived from?”]
[10h] Although Dalmatian embryos contain this structure, they lack its namesake nitrogenous protein because they can’t metabolize uric acid. This extraembryonic membrane exchanges waste between amniote embryos and their surroundings.
ANSWER: allantois (The nitrogenous protein is allantoin.)
[10e] Besides having urate stones, Dalmatians are prone to kidney problems due to their high risk for autosomal Alport syndrome, which deforms the fourth isoform of this abundant triple-helical extracellular matrix protein.
ANSWER: collagen [accept type IV collagen or COL4A3 or COL4A4] (Alport Syndrome is usually X-linked.)
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