Coefficient of Relationship (COR) & It’s Use in Animal Breeding
The Coefficient of Relationship (COR) is an important concept in animal breeding that helps us understand how closely related two animals are. Think of it like figuring out if two people are first cousins, second cousins, and so on. In the world of animal breeding, knowing this relationship is crucial because it helps breeders decide which animals to mate. The goal is to breed healthy animals with the desired traits, like good milk production in cows or friendly temperaments in dogs.
In simpler terms, the COR number tells breeders how much genetic material two animals share. A higher number means they are more closely related. You can then use this information to avoid breeding animals that are too closely related, which can lead to health problems.
Genetics and Heredity
Let’s break down genetics and heredity in a way that’s easy to understand, especially for those new to animal breeding. Think of genetics as the study of the tiny instructions, called genes, that are inside every living creature. These genes are like recipes that tell the animal how to look and act. For instance, genes determine whether a dog has a short or long coat, or if a cat will have blue or green eyes.
Heredity is all about how these genes are passed down from parent animals to their babies. It’s like how children can inherit their parents’ features, such as hair color or height. In animal breeding, this is really important because breeders want to know what traits the baby animals might get from their parents.
If they understand heredity, breeders can choose the best parent animals to get the qualities they want in the babies, like a horse that runs fast or a chicken that lays lots of eggs. Essentially, heredity is the natural way genes are handed down through generations, and understanding it helps breeders create healthier and better-quality animals.
What is the Coefficient of Relation?
The Coefficient of Relation (COR) is a measure that’s very similar to the Coefficient of Inbreeding (COI), but while COI is used to determine how closely related an individual animal is to its ancestors, COR is used to find out what the inbreeding coefficient (COI) would be for the potential offspring of two animals. Essentially, it’s a tool that helps breeders predict how inbred a future puppy, kitten, or calf might be if two specific animals were to mate.
Calculating the COR involves looking at the family trees of both potential parent animals and identifying any common ancestors they have. The more common ancestors, the higher the COR, which would indicate a higher potential COI for their offspring. This is because common ancestors mean that the same genes may be passed down from both the mother and the father, increasing the chances of inbreeding.
Here’s how it’s calculated using a simple example:
- Identify Common Ancestors: Look at the family trees of the two animals to find any ancestors they share. For instance, if we consider two dogs, Max and Bella, we find that they share a grandfather.
- Calculate Shared Genetics: Determine how much genetic material the animals share through these common ancestors. Since Max and Bella share a grandfather, they have some genetic material in common.
- Compute the COR: The COR is calculated based on the shared genetics. If the shared grandfather is their only common ancestor, and assuming each ancestor contributes equally to the genetic makeup, the calculation would go as follows:
- Each parent contributes 50% of the genetics to their offspring.
- The shared grandfather would contribute 25% to each parent.
- Since both animals share this grandfather, the COR would be 25% of 25%, which equals 6.25%.
Inbreeding Coefficient Chart
This chart is a quick guide to help you see how related two animals are and what their inbreeding percentage might be if they have babies together. It’s not fully comprehensive but offers a clear overview of how the COI can vary depending on how closely related two animals are.
For example, direct relationships like parent/offspring or brother/sister have a high inbreeding coefficient of 25%, indicating a significant overlap in genetic material. As the familial connection becomes more distant, like with second or third cousins, the inbreeding coefficient decreases, showing less genetic overlap.
| Relationship | Inbreeding Coefficient (%) |
|---|---|
| Parent/Offspring (Father/Daughter, Mother/Son, Brother/Sister) | 25% |
| Grandparent/Grandchild (Grandfather/Granddaughter, Grandmother/Grandson) | 12.5% |
| Half Siblings (Half-Brother/Half-Sister) | 12.5% |
| Uncle/Niece, Aunt/Nephew | 12.5% |
| Great-Grandparent/Great-Grandchild (Great-Grandfather/Great-Granddaughter, Great-Grandmother/Great-Grandson) | 6.25% |
| Half-Uncle/Niece, Half-Aunt/Nephew | 6.25% |
| First Cousins | 6.25% |
| First Cousins Once Removed or Half-First Cousins | 3.125% |
| Second Cousins or First Cousins Twice Removed | 1.5625% |
| Second Cousins Once Removed or Half-Second Cousins | 0.78125% |
| Third Cousins or Second Cousins Twice Removed | 0.390625% |
| Third Cousins Once Removed or Half-Third Cousins | 0.195% |
View Potential Animal Pairings and COR
Our application makes it easy to find the best matches for your animals and understand the Coefficient of Relationship (COR) for potential offspring. Here’s how you can use it to view potential animal pairings and their corresponding COR and Ancestor Loss Coefficient (AVK):
- Navigate to the Pairings Page: Start by logging into the application and heading to the ‘Pairings’ page. This section is designed to help you explore and analyze possible matches for your animals.
- Search for Your Animal: In the Potential Pairings card, you’ll find a search bar. Here, type in the name of the animal you want to find a match for. As you enter the name, the application will automatically suggest potential pairings.
- Review the List of Potential Pairings: After searching, the application will display a list of potential mates for your animal, complete with detailed information such as the potential offspring’s COR and AVK. This data helps you understand the genetic relationship and diversity that would result from each pairing.
- Add to Your Pairings: Once you find a suitable match, you can add this pairing to your current projects by clicking the plus or add icon on the right side of the pairing. This action saves the pairing to your profile, allowing you to track and manage your breeding plans easily.
