In a large bowl, combine flour, bran, flaxseed, wheat germ, baking powder, baking soda, cinnamon, mace or nutmeg, brown sugar, dried fruit, and sweet potato. Stir in the yogurt, egg, oil, and orange zest and mix until just combined.
With lightly floured hands, knead the dough in the bowl for several minutes. When smooth, turn the dough onto a lightly floured work surface and pat to a thickness of 1/4 inch. Using a cookie cutter or a glass, cut into 2 1/2-inch rounds. Gather the scraps, gently pat into a ball, flatten again, and cut out more scones.
Place the scones on the prepared baking sheet about 1 inch apart. Bake for 8 to 10 minutes, or until golden brown. Serve warm with or without nut butter and jam or marmalade.