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Genetic Risk Calculator (test page for client)

This Genetic Risk Calculator is designed to assist breeders in evaluating the risk of passing on a single autosomal recessive trait. It is based on Mendelian inheritance principles and uses formulas developed by Dr. Jerold Bell in his article “Relative Risk Pedigree Analysis.”

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This tool functions independently and is not connected to any breed registry or database. Users must manually select the appropriate status—such as Carrier, Sibling to Affected, or Sibling to a Carrier—from the dropdown menu based on known information in the pedigree. The calculator will then estimate the predicted genetic risk for the planned breeding.

​🧬 Here’s how it works:

Mendelian inheritance for an autosomal recessive gene assumes:

  • Two alleles per gene (one from each parent)

  • Carrier (C) = One mutated allele

  • Affected (A) = Two mutated alleles

  • Clear (CL) = No mutated alleles

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📊 Risk Outcomes:

If both parents are:

  • Clear x Clear → 100% Clear

  • Clear x Carrier → 50% Clear, 50% Carrier

  • Carrier x Carrier → 25% Clear, 50% Carrier, 25% Affected

Your calculator simulates this by:

  1. Assigning probabilities to statuses like Carrier, Sibling to Affected, Unknown, etc.

  2. Combining probabilities pair by pair up the pedigree (Mendelian-style) using probability rules for inheritance.​

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🧠 Why it's an Estimate:

The tool is probabilistic — especially for "Unknown" and "Sibling" statuses — because it infers likely genotypes based on relationship, not genetic testing.

How to Enter Carrier Status Codes:

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  1. Start by making sure the calculator is reset.  All Carrier Status Codes should be “Unknown”.​

  2. The Reset button at the bottom of the calculator can be used to reset the calculator.

  3. Use the light colored (light Green and Yellow) cells below Sire and Dam blocks to record the carrier status of any Sire or Dam in your pedigree.

  4. Choose one of the following codes from the drop down in each cell

    • "Carrier" of the recessive gene under consideration (the dog is a carrier)

    • "Sibling to an (Obligate) Carrier"

    •  "Sibling to Affected" (to a dog clinically diagnosed as affected)

  5. If you make an error, simply change it to the correct value, or Unknown if you do not have data on that dog

  6. To view results, click on the "Calculate Risk" button at the top of the chart under "Offspring"

Note: It is your responsibility to conduct thorough research on the dogs within the pedigree, including identifying any affected individuals and noting all obligate carriers (i.e., both sire and dam, as well as all related offspring). You are accountable for the accuracy and completeness of the data you enter. The calculator will perform the associated genetic risk calculations.

Please be advised that the results generated by this tool are statistical estimates based on basic Mendelian inheritance principles and do not guarantee specific outcomes from any individual breeding. This tool is intended as a resource for breeders performing pedigree analysis, and the __________ assumes no responsibility for the accuracy of user-submitted data or the results of any breeding decisions made based on this analysis.

© 2005 - 2025 by Susan Reimund

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