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Web Coefficient of inbreeding

About this page

Coefficient of inbreeding

This page repeats some of the functionality of the 'Coefficient of Inbreeding' program which is explained here. This version finds the probability (p) that a consanguineous child in the pedigree is autozygous for an allele inherited from an individual in the pedigree who is a common ancestor of both of the child's parents. The program also calculates the F (coefficient of inbreeding) and R (coefficient of relationship) for the child's parents.

The structure of the input text and an explaination of the results text is shown at bottom of the page.


Copy and paste the pedigree data in the text box below and then press the 'Submit'.

Pedigree file structure

The pedigree data is imported as simple multiline text, where each line represents a single individual and identifies his or her parents. This is done by first entering the person's ID number, then the father's ID and finally the mother's ID, with each ID number separated by a space. A person must have either both parents in the pedigree or neither parent in the pedigree (i.e. that person is a founder). If neither parent is in the pedigree, both parent ids are set to 0.

A sample pedigree and its results can be imported by pressing .

For example, a pedigree with two parents and a child is written as:

1 0 0 (first founder parent)
2 0 0 (second founder parent)
3 1 2 (first child of parents 1 and 2)

If the child in the pedigree (individual 3) had a child the pedigree becomes:

1 0 0
2 0 0
3 1 2
4 0 0 (partner of person 3)
5 3 4 (child of person 3 and person 4)

When you press the submit button the program will check the file structure and highlight any errors and automatically calculates the p, F and R values for any consanguineous people in the pedigree and displayed it in the lower text box. None consanguineous people are ignored, while if the pedigree contains a circular reference (e.g. a person is erroneously set as their own grandparent), this will be stated in the results text box and the analysis will be terminated.

Sample output data and explanation.

  PersonpFRPedigree size: 17
  15 (11/12) 0.03125 0.0625 0.125
  16 (13/14) 0.0625 0.125 0.25
  17 (15/16) 0.093750.1875 0.375
  • Person:
    This column lists the ID numbers of any consaguineous people in the pedigree with thier parents IDs in brackets.
  • p:
      This shows the probability that the person is autozygous for an allele with respect to the whole pedigree.
  • F:
     This is the persons coefficient of inbreeding with respect to the whole pedigree.
  • R:
     This is the coefficient of relationship for the person, with respect to the whole pedigree.
  • Pedigree size:
     Finally this shows the number of people in the pedigree.

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