Preheat oven to 350 degrees. Place red, white, and/or blue paper baking cups into 24 regular size muffin cups.
Make cake mix as directed on box for cupcakes, using water, oil and egg whites. Divide batter evenly among muffin cups. Add 1 teaspoon of jam to each cup and swirl with a toothpick. Bake 18-20 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove cupcakes from pans to cooling racks. Cool completely.
Tint 1 container frosting with red food color; tint second container with blue food color. Leave third container white. Spoon each color of frosting into separate decorating bag fitted with large round tip. Pipe frosting as desired onto cupcakes. Sprinkle with red, white and blue sprinkles. Refrigerate cupcakes until ready to serve.
Seedless strawberry or raspberry jam can be used in place of blackberry.