|number of generations:||Common Ancestors:||Filtered:|
(n,m X p,q) means: common ancestor occurs in n-th and m-th generation in sire branch and occurs in p-th and q-th generation in dam branch of the pedigree.|
n * (1 + m) means: n is the total factor depending on generations where common ancestor occurs.
If n = 0 then there is always one or more common offspring in both pedigree paths from dam/sire to the occurrence of that ancestor.
If m > 0 means that the common ancestor is inbred itself.
The COI contribution is given in decimals. The total COI is visible as a percentage in the Generation 0 field in the diagram above.
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About this calculation: (status = under construction)|
The formula used in this calculation is Wright's Equation as depicted to the left.
The calculation is done as follows:
A pedigree is computed from the data by a recursive function for a given amount of generations (list #G) starting with a given individual (list G0).
All ancestors are noted for the Branch of the Pedigree they occur in (Dam's and/or Sire's).
Then all ancestors are checked if they occur in both Branches and for which generations. If yes then they are a "common ancestor".
For each common ancestor all occurrences in the sire branch are plotted against the occurrences in the dam branch.
If the plotted occurrences have the same offspring in their path, that contribution is ignored because it is handled by this offspring's contribution.
For each plot the formula is applied. The sum of all these COI contributions is the total COI, or Fx in the formula.
In the formula n1 is the number of generations from the common ancestor to the sire in the sire's branch and n2 is the number of generations from the common ancestor to the dam in the dam's branch.
FA is the COI of the common ancestor if it is inbred itself.
To calculate this each common ancestor from earlier generation to the present is calculated first and this value is put in FA.
The factor (1/2) is the chance that the parent passes one of his two "copies" of a gene to his offspring.
The COI ( Coefficient of Inbreeding ) therefor represents a chance that the offspring has got two identical copies from it's ancestors by inbreeding.
The danger of inbreeding being the accumulation of harmful recessive mutations.