Understanding the Basics

This powerpoint presentation was given during the ILU meeting 2018 by Rob Lyon.

 

 

 

 

Mean Kinship

Understanding the Basics

 

 

 

 

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Quick Starter ….

Mean Kinship is NOT a Health Measurement !!!!!

  • Mean Kinship is a measurement of Genetic Diversity. It tells us NOTHING about the health of an individual dog
  • Mean kinship ONLY tells us the relatedness of each animal with the entire current population.

Mean Kinship is NOT the only important thing !!!!

  • Good choices about other heath tests come FIRST. Before you consider MK, you must consider Hips, Elbows, Eyes and all the other factors that make a good mating choice. Do not start by looking at MK.

The differences between High and Low MK values are very small !!!!

  • MK values are highlighted using color bands. These colors are only to make it easy to see the differences.

MK tells us we should try to include MORE dogs in our breeding programs !!!!

  • To maintain diversity we should look for more dogs to breed with instead of over using the same sires.

 

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Inbreeding Our Dogs

Advantages

  • Increased Uniformity – Our dogs look more alike
  • Increased Pre Potency – We get the Characteristics and Features we want
  • Fixes Genes for “Type” – We get a consistent type

Disadvantages

  • Lower Fertility – Failed matings become more common
  • Genetic Defects – Faults and inherited diseases can become more common.
  • Lower Fitness – Reduced Health, Lifespan and “Vigour”
  • Less Genetic Variation – Fewer Options to Correct Undesirable Traits

 

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How Is Diversity Lost ?

Selective breeding affects the composition of the gene pool

  • Genetic diversity can be lost from the gene pool because of selection - some dogs are bred but most are not.​
  • Some animals have a disproportionate number of offspring, and their genes become over-represented. The best example of this is the “popular sire”.
  • Popular sires reduce the size of the gene pool because they deprive other males of reproductive opportunities.
  • Popular sires also drive up the average level of relatedness in the population because of the number of siblings and half-siblings that share the same genes from that sire.

 

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What Happens When Diversity Is Lost

  • Most genetic disorders in dogs are caused by recessive mutations that originate with a single Sire
  • Overuse of the Sire leads to excessive spread of the recessive genes from that sire.
  • Previously unknown genetic conditions like LPN and LEMP begin to appear in the breed.
  • Cancer rates increase. Tumour Suppression depends on a healthy immune system.

 

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Avoiding New Genetic Disorders

  • We can solve the problem of genetic disorders in dogs faster and better by using proper genetic management.
  • Low inbreeding will reduce risk of ALL disorders caused by recessive mutations.
  • Minimize loss of genetic diversity so you don’t lose important genes. They’re all important
  • The best protection we have against the spread of new genetic mutations like LPN and LEMP is to ensure that Genetic Diversity is maintained.

    • MEAN KINSHIP IS THE TOOL THAT HELPS US DO THIS

 

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What Is Mean Kinship

  • Kinship is a measure of the importance of an animal for maintaining genetic variation within the entire breed.

  • Animals with low kinship are genetically diverse compared to others and should be used more often for breeding.

  • Animals with high kinship have less genetic variety compared to others and should be used less often for breeding.

  • The actual value of kinship is less important. The value compared to other animals is more important.

 

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How is Mean Kinship Calculated

  • Mean kinship is calculated by the comparing the relatedness of each animal with the entire current population.

  • Calculation of MK needs a (almost) complete Pedigree Database.

  • The individual Kinship of every dog to all other dogs in the database is calculated.

  • The Mean Kinship of a Leonberger is the “Mean” (or average) of all individual kinships.

  • The Mean Kinship of each Leonberger is divided into one of three groups, “Orange”, “Yellow” and “Green”. These groups are just for comparison.

 

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Using Mean Kinship

Mean Kinship is a tool for deciding on Overall Breeding strategy

  • A High (Orange) Kinship value is not a reason to reject a Leonberger from breeding.

  • Low (Green) Kinship Numbers are preferred where it is desired to introduce more genetic variation into a group of Leonbergers.

  • Dogs with Green Kinship Values are Highly Desirable for import into countries where diversity is low.

 

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Mean Kinship is not a Substitute for COI.

Mean Kinship Describes the WHOLE Leonberger Gene Pool

  • Mean Kinship is a measure of the Genetic Diversity of the ENTIRE Leonberger population.
  • The Kinship of a single dog is compared against the rest of the ENTIRE Leonberger population.
  • The Kinship of a single dog says NOTHING about the relatedness to another SINGLE Leonberger.

COI Describes the Relationship of TWO Leonbergers.

  • COI describes the Genetic Relationship between two INDIVIDUAL Leonbergers.
  • COI says Nothing about the genetic diversity of the ENTIRE Leonberger population.

 

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Comparing COI and MK

Imagine mating two siblings from the same “Green” litter

  • The COI would be excessively high

    - The parents are siblings.

  • The Mean Kinship of the pups would be low

    - The pups are genetically diverse compared to the rest of the entire Leonberger population

    • COI is a tool for deciding on Individual mating choices.
    We need to consider COI AND Mean Kinship

 

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Updating Mean Kinship

  • Mean Kinships per animal are relative to the current population.
  • This means that the Mean Kinship of a specific animal will change over time when a population changes. For example, Mean Kinship will increase each time an animal produces progeny.
  • Mean Kinship will also change as the Pedigree Database changes. If we find new Founders or if we find new unregistered dogs then MK numbers will change.
  • So the Mean Kinship Calculations must be repeated periodically.

 

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More Information ……

End of presentation