While looking at different recipes to make "yogurt sauce" commonly found in Middle Eastern cuisine, I noticed a descrepancy between the type of yogurt the recipe calls for. Some recipe calls for plain low fat yogurt, others calls for plain Greek yogurt, and then in this recipe, it calls for strained plain yogurt: http://allrecipes.com/recipe/tzatziki-sauce-yogurt-and-cucumber-dip/.
What type of yogurt should be used to make the most authentic yogurt sauce? Is there a specific type of yogurt or specific brand that most closely resemble the yogurt used in the Middle East?