A researcher wanted to create a loss of function mutation for studying Type I Diabetes in a model animal. What mutation would mimic Type I diabetes? a) Inhibition of sugar absorption in the small intestine
b) Inhibition of pancreatic beta-cells
c) Up regulation of insulin receptors on the pancreas
d) Down regulation of GLUT4 transporters in muscles

The correct answer is: b) Inhibition of pancreatic beta-cells.

Explanation:

Type 1 Diabetes is a form of Diabetes Mellitus, a condition characterized by chronic hyperglycemia (high blood sugar levels) that can compromise many organs and even cause death if not treated properly.

The most common form of Diabetes Mellitus is Type 2 Diabetes, in which the pancreas produces insulin but cannot reach the target organs because of a pathologic state called Insulin Resistance.

Type 1 Diabetes, instead, is present in patients that cannot produce insulin on their own. Insulin is the most important hormone in the regulation of blood sugar - it is secreted by the pancreatic beta-cells when glycemia rises (which is normal after eating) and it is key in allowing glucose to reach the tissues where it's needed for energy requirements. Type 1 Diabetes is usually diagnosed in young, even pediatric, patients - the pancreatic beta-cells in these individuals are destroyed and unable to function (the reason for this is not clear in all cases), so they have to be administered with exogenous insulin to survive.

For the model animal to better represent Type 1 Diabetes, the mutation would have to inhibit pancreatic beta-cells.

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