Related Clues:

• Quirk of behavior
• Unconscious quirk
• Hair color, e.g.
• Start of a simple game
• First X, maybe
• It may be inherited
• Muscle spasm
• Marvel
• Sudden contraction
• Sign of nerves
• Irregularity
• It may be passed down the line
• Muscle contraction
• Earmark
• Three-legged calf, e.g.