Free Pedigree Chart Maker
Map hereditary disease patterns, inheritance modes, and carrier status across generations — no signup, no cost.
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A pedigree chart is a standardized diagram used in genetics and genetic counseling to map the occurrence of a specific trait or hereditary condition across multiple generations of a family. Using internationally recognized symbols from the National Society of Genetic Counselors, a pedigree chart makes inheritance patterns immediately visible — whether a condition follows autosomal dominant, autosomal recessive, X-linked, or mitochondrial inheritance. It is a foundational tool in clinical genetics, biology education, and patient counseling.
How to make a pedigree chart
Describe the family and the condition
Write a description of the condition you are mapping, the number of generations, and which family members are affected, carriers, or unaffected. Include the suspected inheritance pattern if known.
Generate the pedigree
FreeDiagram produces a properly notated pedigree chart following NSGC conventions: squares for males, circles for females, filled shapes for affected individuals, half-filled for carriers, and open shapes for unaffected.
Label generations and the proband
Generations are numbered with Roman numerals (I, II, III) on the left side. The proband — the first family member identified with the condition — is marked with an arrow. Add age at diagnosis or other annotations as needed.
Export or embed
Download the pedigree chart as a PNG or SVG for use in clinical reports, patient education materials, research papers, or biology coursework.
About pedigree charts
Pedigree charts have been used in genetics since the early twentieth century, but the modern standardized notation was formalized by the National Society of Genetic Counselors and published in the American Journal of Human Genetics. The NSGC symbol set is now the international standard for clinical pedigrees and is required in most peer-reviewed genetics publications and clinical genetics reports.
The core symbols are intentionally simple. Squares represent males; circles represent females; a diamond is used when sex is unknown or for non-binary individuals. A filled shape indicates an affected individual. A half-filled shape indicates a carrier who does not express the condition but can pass it to offspring. An open shape indicates an unaffected, non-carrier individual. A line through any shape indicates the individual is deceased.
Generations are arranged horizontally in rows, labeled with Roman numerals along the left margin (Generation I at the top, the most recent generation at the bottom). Within each generation, individuals are numbered from left to right. The proband — the first family member who presented to medical attention and prompted the pedigree to be drawn — is marked with an arrow pointing to their symbol. The consultand, the individual seeking genetic counseling, may be marked differently if they are not the proband.
Pedigree charts are distinct from genograms in their purpose and notation. A genogram is a clinical tool for mapping family relationships and emotional dynamics, used primarily in psychotherapy and social work. A pedigree chart is a scientific tool for tracing the inheritance of a specific biological trait, used in genetics and medicine. While both use squares and circles, a pedigree follows the stricter NSGC notation and focuses entirely on the presence or absence of a heritable condition.
Frequently asked questions
What is the standard notation for a pedigree chart?
The standard notation is defined by the National Society of Genetic Counselors (NSGC). Squares represent males, circles represent females, and diamonds represent individuals of unknown or non-binary sex. Filled shapes indicate affected individuals, half-filled shapes indicate carriers, and open shapes indicate unaffected individuals. A horizontal line through a shape indicates the individual is deceased.
What is the proband in a pedigree chart?
The proband is the first family member identified with the condition being studied — the person whose diagnosis prompted the construction of the pedigree. The proband is indicated by an arrow pointing to their symbol. In a clinical setting, the proband is often (but not always) the patient who sought genetic counseling.
How is a pedigree chart different from a genogram?
A pedigree chart tracks the inheritance of a specific biological trait or disease using NSGC notation and is used in genetics and medicine. A genogram maps family relationships, emotional bonds, and psychosocial patterns and is used in clinical social work and family therapy. They use overlapping symbols but serve different disciplines and answer different questions.
Can I use this pedigree maker for a biology class assignment?
Yes. FreeDiagram can generate pedigrees for common genetics problems — autosomal dominant, autosomal recessive, X-linked recessive, X-linked dominant, and mitochondrial inheritance — which are the standard inheritance types covered in high school and university biology courses.
How do I show a carrier in a pedigree chart?
Carriers are shown as half-filled shapes — a circle with the left or right half filled in for a female carrier, or a square with one half filled in for a male carrier. In X-linked conditions, carrier females are always shown with the half-filled circle because they carry the allele on one X chromosome but do not typically express the condition.
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