How to draw your pedigree
A pedigree, or drawing of a family tree, is a pictorial representation of a family. The construction of an accurate
family pedigree is fundamental to the provision of clinical genetics services and serves as an informational
framework for human genetic research. Its great strength is that it allows a lot of clinical and family information
to be seen at a glance.
The basics
As shown below, males are depicted as squares, females as circles, and individuals of unknown sex as
diamonds. A union (previously used to show a marriage, but now shows a broader spectrum of relationships) is
shown by connecting two individuals with a solid horizontal line. This line is called the "relationship" line.
Usually the male is drawn to the left of his female partner. If the union is between individuals that are related to
each other (have a common ancestor) the relationship line is a doublet. If the union produces any children or
pregnancies, a vertical line is drawn from the relationship line. This vertical line is called the "line of descent".
The line of descent may connect to a horizontal "sibship" line. "Individual" lines from the sibship line are drawn
to an individual's symbol to show a child of the union.
Special symbols
Pregnancies are drawn as triangles, or diamonds with a capital 'P' in the center (if the sex of the pregnancy is
known, a square or circle with a 'P' can be used). Twins (or triplets) are drawn like cherries off of the sibship
line. Individuals who have passed away have a diagonal line drawn through their symbols. An individual's
symbol may be shaded or hatched to show particular clinical status, which is interpreted in a legend or key. It is
not uncommon to see notations next to an individual's symbol. These notations may state the individual's date of
birth or other information of interest.
How to draw your pedigree
A pedigree, or drawing of a family tree, is a pictorial representation of a family. The construction of an accurate
family pedigree is fundamental to the provision of clinical genetics services and serves as an informational
framework for human genetic research. Its great strength is that it allows a lot of clinical and family information
to be seen at a glance.
The basics
As shown below, males are depicted as squares, females as circles, and individuals of unknown sex as
diamonds. A union (previously used to show a marriage, but now shows a broader spectrum of relationships) is
shown by connecting two individuals with a solid horizontal line. This line is called the "relationship" line.
Usually the male is drawn to the left of his female partner. If the union is between individuals that are related to
each other (have a common ancestor) the relationship line is a doublet. If the union produces any children or
pregnancies, a vertical line is drawn from the relationship line. This vertical line is called the "line of descent".
The line of descent may connect to a horizontal "sibship" line. "Individual" lines from the sibship line are drawn
to an individual's symbol to show a child of the union.
Special symbols
Pregnancies are drawn as triangles, or diamonds with a capital 'P' in the center (if the sex of the pregnancy is
known, a square or circle with a 'P' can be used). Twins (or triplets) are drawn like cherries off of the sibship
line. Individuals who have passed away have a diagonal line drawn through their symbols. An individual's
symbol may be shaded or hatched to show particular clinical status, which is interpreted in a legend or key. It is
not uncommon to see notations next to an individual's symbol. These notations may state the individual's date of
birth or other information of interest.
How to draw your pedigree
A pedigree, or drawing of a family tree, is a pictorial representation of a family. The construction of an accurate
family pedigree is fundamental to the provision of clinical genetics services and serves as an informational
framework for human genetic research. Its great strength is that it allows a lot of clinical and family information
to be seen at a glance.
The basics
As shown below, males are depicted as squares, females as circles, and individuals of unknown sex as
diamonds. A union (previously used to show a marriage, but now shows a broader spectrum of relationships) is
shown by connecting two individuals with a solid horizontal line. This line is called the "relationship" line.
Usually the male is drawn to the left of his female partner. If the union is between individuals that are related to
each other (have a common ancestor) the relationship line is a doublet. If the union produces any children or
pregnancies, a vertical line is drawn from the relationship line. This vertical line is called the "line of descent".
The line of descent may connect to a horizontal "sibship" line. "Individual" lines from the sibship line are drawn
to an individual's symbol to show a child of the union.
Special symbols
Pregnancies are drawn as triangles, or diamonds with a capital 'P' in the center (if the sex of the pregnancy is
known, a square or circle with a 'P' can be used). Twins (or triplets) are drawn like cherries off of the sibship
line. Individuals who have passed away have a diagonal line drawn through their symbols. An individual's
symbol may be shaded or hatched to show particular clinical status, which is interpreted in a legend or key. It is
not uncommon to see notations next to an individual's symbol. These notations may state the individual's date of
birth or other information of interest.
How to draw your pedigree
A pedigree, or drawing of a family tree, is a pictorial representation of a family. The construction of an accurate
family pedigree is fundamental to the provision of clinical genetics services and serves as an informational
framework for human genetic research. Its great strength is that it allows a lot of clinical and family information
to be seen at a glance.
The basics
As shown below, males are depicted as squares, females as circles, and individuals of unknown sex as
diamonds. A union (previously used to show a marriage, but now shows a broader spectrum of relationships) is
shown by connecting two individuals with a solid horizontal line. This line is called the "relationship" line.
Usually the male is drawn to the left of his female partner. If the union is between individuals that are related to
each other (have a common ancestor) the relationship line is a doublet. If the union produces any children or
pregnancies, a vertical line is drawn from the relationship line. This vertical line is called the "line of descent".
The line of descent may connect to a horizontal "sibship" line. "Individual" lines from the sibship line are drawn
to an individual's symbol to show a child of the union.
Special symbols
Pregnancies are drawn as triangles, or diamonds with a capital 'P' in the center (if the sex of the pregnancy is
known, a square or circle with a 'P' can be used). Twins (or triplets) are drawn like cherries off of the sibship
line. Individuals who have passed away have a diagonal line drawn through their symbols. An individual's
symbol may be shaded or hatched to show particular clinical status, which is interpreted in a legend or key. It is
not uncommon to see notations next to an individual's symbol. These notations may state the individual's date of
birth or other information of interest.