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:
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Two alleles per gene (one from each parent)
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Carrier (C) = One mutated allele
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Affected (A) = Two mutated alleles
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Clear (CL) = No mutated alleles
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📊 Risk Outcomes:
If both parents are:
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Clear x Clear → 100% Clear
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Clear x Carrier → 50% Clear, 50% Carrier
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Carrier x Carrier → 25% Clear, 50% Carrier, 25% Affected
Your calculator simulates this by:
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Assigning probabilities to statuses like Carrier, Sibling to Affected, Unknown, etc.
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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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Start by making sure the calculator is reset. All Carrier Status Codes should be “Unknown”.​
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The Reset button at the bottom of the calculator can be used to reset the calculator.
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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.
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Choose one of the following codes from the drop down in each cell
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"Carrier" of the recessive gene under consideration (the dog is a carrier)
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"Sibling to an (Obligate) Carrier"
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"Sibling to Affected" (to a dog clinically diagnosed as affected)
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If you make an error, simply change it to the correct value, or Unknown if you do not have data on that dog
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To view results, click on the "Calculate Risk" button at the top of the chart under "Offspring"