Pedigree Chart Symbols and Meanings

A pedigree chart is a tool similar to a family tree, but it is used for genetic or genealogical research. It uses specific pedigree symbols for the occurrence and appearance of a gene-phenotype from one generation to the next. A pedigree chart is used for humans but also useful for dogs and horses lineage.

1. What are Pedigree Symbols

The pedigree symbols are used in genetics diagrams to trace the inheritance of an abnormality, disease, or inheritance of a specific trait. There are particular pedigree symbols for male and female, marriage lines, offspring lines, and multiple births, etc.

A clinical pedigree must include the name of the consultand, name and designation of the person recording it, historian, and date and reason for taking the pedigree. Then comes the basic family information with a family pedigree symbol for every individual. The main data for every individual includes.

  • First name, or initials that go below the symbol.
  • The current age also goes below the symbol.
  • The disease or disorder of the individual also goes below the symbol with the age of onset.
  • Draw the person's parents.
  • Include the parents' current age, or age at death.

Shading also has a specific meaning in pedigree symbols. For example:

  • A half-shaded circle or square represents that a person is a carrier of the trait in question.
  • A completely shaded circle or square shows a person who expresses the trait.
  • A non-shaded circle or square represents a person who is not expressed or carrier of the trait.

2. Basic Pedigree Symbols

Ladder diagrams symbols are the basic building blocks of a Ladder Circuit Diagram and these symbols are used in the PLC Programming. Here are some Symbols which are given below with their names and we also provide a symbol table, there you can find all ladder symbols with their names and their description.

Symbol Name Description
ladder diagram NO symbol Female A pedigree symbol circle represents an individual whose gender is female. Individuals are the main component of a pedigree chart.
ladder diagram NC symbol Male A pedigree symbol square represents an individual whose gender is male.
output coil symbol Undefined Gender An individual of unknown or undetermined gender.
one shot symbol Pregnant - unknown gender Pregnant, but the gender of the fetus is unknown. EDD is the expected due date.
set coil symbol Pregnant - female gender Pregnant with a female fetus.
reset coil symbol Pregnant - male gender Pregnant with a male fetus.
timer delay on symbol Affected female A female who is affected by the disease.
timer delay off symbol Affected male A male individual who is affected by the condition.
ladder diagram greater than equal to symbol Adopted male The adopted male child in the family.
ladder diagram less than equal to symbol Adopted female Adopted female child in the family.
ladder diagram equal to symbol Deceased male Deceased male individual. The age of the member of the date of death will go under the symbol.
adder symbol Deceased female Deceased female.
subtractor symbol Multiple diagnoses Multiple diagnoses of the same individual.
multiplication symbol Multiple individuals The number of siblings is written inside the symbol.
division symbol Stillbirth (SB) Birth of a dead child. The gestational age goes under the symbol.
PID-controller symbol Pregnancy (P) Gestational age and karyotype (if known) below symbol. Light you can use shading for affected and defined in key/legend.
counter up symbol Consultand Individual(s) seeking genetic counseling/testing.
counter down symbol Miscarriage Pregnancy terminated by a miscarriage.
counter down symbol Elective AB Elective abortion.

3. Pedigree Line Definition

Different types of lines show different types of relationships, hierarchies, and connections. Each line has a special meaning about the pedigree symbols used in the chart.

3.1 Definition of Pedigree Line

1. Relationship Line

Relationship lines are horizontal lines that show marriage, divorce, or another relationship status. A horizontal line is also used to mark areas of support or resistance in technical analysis. A horizontal line runs parallel to the x-axis.

counter down symbol counter down symbol

2. Line of a Descent

A vertical relationship line is a line of descent that shows the relationship and transmission of traits or diseases from the previous generation. A break or disjoint shows a broken relationship.

counter down symbol counter down symbol

Dizygotic Twins are non-identical twins. They are represented by two diagonal, vertical lines coming from the same point of origin.

counter down symbol

Monozygotic twins are identical twins represented by horizontal lines connecting the two diagonal lines that lead down to the gender symbols. Some pedigree charts also use a pedigree symbol that displays a horizontal line connecting the two gender symbols to create a triangle shape at the origin.

counter down symbol

No children of a member are represented by a vertical line with two hash marks at the end. A 'c' letter Indicates that an adult does not have children by choice, and an 'i' shows infertility.

counter down symbol

3. Sibship Line

The siblings are connected through a horizontal sibship pedigree symbol. The siblings are placed in order of birth from left to right.

counter down symbol

4. Consanguineous Lines

Consanguineous matings are those in which individuals share a common ancestor. Double lines between pedigree symbols represent it. If the degree of relationship is not obvious from pedigree hierarchy, it is stated above the relationship line—for example, third cousins.

counter down symbol

4. Tips for Using Pedigree Symbols

EdrawMax Online is a premium drawing software that supports more than 280 types of diagrams and drawings. It is well stocked with comprehensive symbols, an easy-to-use drag and drop layout, and an excellent collection of professional quality templates.

You can use the exclusive pedigree symbols to draw professional, correct, and efficient pedigree charts that deliver a wealth of information. You can even save time and effort by using the fully customized templates available at Template Community for a quick start. Here are some tips for using EdrawMax to draw pedigree charts.

Step 1: Find pedigree symbols at EdrawMax Online > Symbol Library > Family Tree > Genogram.

step 1

Source: EdrawMax Online

Step 2: EdrawMax Online has a comprehensive symbols library for family trees, genograms, and pedigree symbols. However, if you require any symbols not available in the program, you can also import your customized symbol files. Easily import symbols as images, symbols, or data from files format such as SVG, VSSX, etc. You just have to navigate to the library option on the left-hand sidebar and click on the import icon. In the new window, you will find options for importing your file in different formats.

step 2

Source: EdrawMax Online

You can also learn more from this video. YouTube.

5. Conclusion

Pedigree Chart helps in tracing certain phenotypes of genes within an ancestry. These charts are used for humans to determine genetic disorders and to predict possible illnesses in individuals. In contrast, animal breeders use them for checking the breeds of dogs and horses etc.

Pedigree symbols make it very easy for researchers to study the complete gene history of a family in a single chart with the help of visual elements. You can easily and efficiently draw pedigree charts in EdrawMax with the support of its comprehensive library and excellent collection of pre-made templates.

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