Pedigree Symbols and Notation, Fully Explained
Every pedigree symbol decoded: squares, circles, diamonds, shading, carrier dots, proband arrows, deceased slashes, twin bars, consanguineous double lines, and adoption brackets.
- notation
- basics
- reference
The power of a pedigree is that the symbols are a standard. Here’s the complete set, grouped the way you’ll actually use it.
People
| Symbol | Meaning |
|---|---|
| Square | Male (assigned male at birth) |
| Circle | Female (assigned female at birth) |
| Diamond | Sex unknown / not reported |
| Small triangle | Pregnancy |
| Small triangle with number | Multiple pregnancies, details unknown |
Trait status
| Mark | Meaning |
|---|---|
| Filled / shaded | Affected |
| Dot in center | Unaffected carrier |
| Half-filled | Presymptomatic |
| Diagonal slash | Deceased |
| Arrow | Proband (family member who initiated the study) |
| Unlabelled arrow | Consultand |
Relationships
- Single horizontal line — union of two partners.
- Double horizontal line — consanguineous union (blood relatives).
- Slashed line — former union (separated/divorced).
- Vertical line — descent from the union to the children.
- Horizontal sibling bar — children of one union.
- Bar on top, joined siblings — monozygotic (identical) twins.
- Inverted V joining siblings — dizygotic (fraternal) twins.
- Dashed vertical line — uncertain connection / unknown parent.
- Brackets facing the child’s family — adopted in; facing away — adopted out.
The two profiles
Most charts use the modern profile above. A small variant, often called “classroom legacy,” changes the carrier dot and pregnancy marks to match older textbooks. The maker lets you switch the whole chart between profiles in one setting — pick whichever your course or journal expects.
Where to see each symbol
Every mark above is used somewhere in the example charts. The fastest tour: open the twins template (twin bars, former unions), the adoption template (brackets, dashed lines), and any inheritance template (shading, carriers, proband, consanguinity). Each opens as an editable project so you can inspect how the notation is drawn.
For the printable one-page version of this guide, see the symbols guide.