Mendelian and population genetics in animal breeding

Question 1

What are mutations in genetics?

Answer 1

Changes in the DNA

Question 2

What is gene flow?

Answer 2

Any movement of genes from one population to another- important for genetic variation

Question 3

What can cause genetic variation?

Answer 3

• Mutations.
• Gene flow
• Sex: crossing over

Question 4

What are germ line mutations?

Answer 4

They can be passed from one generation to the next

Question 5

What is the genotype frequency?

Answer 5

The proportion of animals with each genotype

They are expressed as a fraction of one whole e.g. 100 cows, 60 red, 40 white= 0.6R and 0.4W

Question 6

What is the Hardy-Weinberg law?

Answer 6

Genotype frequencies in offspring depend solely on gene frequencies in parents.

Question 7

What at qualitative traits?

Answer 7

• Normally fairly dramatic
  e. g. coat colour, absence of horns, double muscle

(Note: think of Qualitative as purely genetic and discontinuous, whereas gualitative has a numerical value and is affected by environmental factors )

Question 8

What is responsible for double musculature in the Belgian blue?

Answer 8

-Mutation to the myostatin gene

Question 9

Discuss double musculature in whippets

Answer 9

Two copies of mutated myostatin gene:

• If they are homozyngous for it then they have large amount of extra muscle and tend to perform worse
• If they are heterozygous then they tend to have a smaller amount of extra muscle and have an increased performance level

Question 10

List some diseases that are considered qualitative traits

Answer 10

• Susceptibility to scrapie in sheep (due to Prp gene)
• Canine haemophilia B
• Muscular dystrophy in retrievers