A circle with shading represents
Pedigree symbols encode both sex and disease status visually for rapid interpretation. Circle denotes female individual, square male. Solid filled or shaded symbol indicates affected phenotype expressing trait under investigation, while open unfilled symbol denotes unaffected healthy status. Half-filled symbol indicates heterozygous carrier for autosomal recessive or X-linked conditions with normal phenotype. Therefore circle with complete shading represents affected female, distinct from square shaded for affected male and half-shaded circle for carrier female. Mastery of conventions enables
Ref: Griffiths et al., Introduction to Genetic Analysis, 12th ed., Chapter 2: Pedigree Symbols and Shading
