RATIONALE

Many of us consider our dog to be a best friend.  There are those who are known to talk to horses.  This personification of our pet runs so deep that "Scout" often times becomes a member of the family, and Arrowman's 30 year run as a riding companion will end only too soon.

In this simple affection lies a very complex question: what are the ethics within our society and ourselves that allow us to manipulate the breeding of animals and not that of people?  Although some of the impetus behind doctoring the breeding of dogs or horses is purely financial, there are in fact  altruistic reasons: we do not like to see our "friends" suffer and we think that we can prevent certain diseases.

EXPLORATION QUESTIONS

Select either a horse or a dog as your research subject and use the resources below to answer the following:

1. What are the purposes of your search?  What is the genetic abnormality that you have chosen to explore?

2. What are the visible and/or non-visible indications of this disease?

3. How has technology helped breeders better understand this disease?

4. What is an example of a genotype for each parent (dogs - sire/dame  horses - stallion/mare) which could represent that they are carriers of a chosen disease? 

5.  Create a Punnett square representation of the sample space for the breeding of two dogs or horses who could pass this gene on to their pups or foals.    What is the probability that a pup or foal will have the genotype for the disease?  What is the probability that the pup or foal will have the phenotype for the disease?

6.  How would these probabilities change for siblings of a single pup or foal? Use your understanding of independent vs. dependant events  and the fact that most dogs have more than one pup and horses could in fact have twins.

7.  Has the discovery of the genetic coding responsible for this disease made life easier or more difficult for the breeders?  Why?

8.  Given the information from your answers above, what would your recommend to a breeder concerning each of the parents?  Why?

9.  Has this exploration changed your views or given you an opinion about human genetic manipulation? 

REFERENCES

DOGS

The Dog Genome Project

Good Hips Bad Hips?  - a close look at the boarder collie and hip displasia

Hip Dysplasia -  a series of very informative articles about this genetic disease; includes great human genetic analogies (re: genotype and phenotype explanation, co-dominance)

Heredity Diseases - diseases that are genetically transmitted.

What you should know

Vet Gen - a company invested in selling DNA testing for dogs.

Australian Sheep Dogs

Dog Related Links

The Horse Genome Project

Horse Genetics

HYPP (CELERA)  Many foals inherit this potentially lethal disease without the knowledge of the breeders.

HYPP (UC DAVIS)

LWO Many horse breeders are in the business of breeding a pattern of horse the is refered to as Overo.  What they are finding is that this could be a lethal proposition for some foals.

UC DAVIS - GENERAL INFORMATION