A pedigree chart is a tool for genetic or genealogical research. It is similar in structure to a family tree, but is more of a working document. It may include specific information about an area of study, such as hereditary diseases, for example. A pedigree chart may be used for humans, but can also be useful for studying the lineage of show dogs and race horses.
Each box in a pedigree chart includes the ancestor's name, as well as space to record critical information about his or her life, such as birth date and location, death date and location, and marriage date and location. Genetic information may also be listed, depending on the purpose of the chart.
How to Use Pedigree Charts
Pedigree charts are useful in the genetic study of both humans and animals. Such charts are particularly beneficial when studying the occurrence a genetic condition over several generations. Pedigree charts are commonly used in families to track genetic diseases and calculate the probability of a child having a disorder in a particular family. In the practice of selective animal breeding of livestock, including horses and dogs, pedigree charts are used to assist in planning a suitable breeding program to enhance desirable traits.
Best Practices When Creating a Pedigree Chart
- Start your chart. Begin your chart with the father and mother. If either of them has a genetic condition, mark that in the chart. For animal breeding programs, make sure to mark any important identifying characteristics for that breed as well as accurate birth and death dates.
- Create branches. Make branches coming from the father and mother to each of the children or offspring. As a best practice, organize them for oldest to youngest from the left. If any of the children have the genetic condition or in the case of animals, a specific characteristics, mark that as well. Add a line to each child who marries. For each couple, repeat the process.
- Add generations. As you add generations, label each generation using Roman numerals (I, II, III, and so on). The original set of parents, located at the top or far left, are generation I. Continue the sequential numbering to their children, grandchildren, great grandchildren and so forth. Each individual within the same generation is labeled using an Arabic number (1, 2, 3, and so on).