Genetics

Question 1

What’s Mendel’s 1st law?

Answer 1

Law of segregation - alleles segregate from one another at gamete formation

Question 2

What’s Mendel’s 2nd law?

Answer 2

Law of independent assortment - During gamete formation, alleles from different genes segregate independently

Question 3

What’s Mendel’s 3rd law?

Answer 3

Recessive alleles will always be masked by dominant alleles

Question 4

What’s the difference between incomplete dominance and co dominance?

Answer 4

Incomplete dominance - occurs when phenotype Is distinct & often an intermediate between the two phenotypes. e.g red and white flower produce pink offspring

Co-dominance - both alleles contribute to phenotype and can both be seen. no intermediate. e.g bloody type

Question 5

What is epistasis?

Answer 5

Phenotype caused by one gene influenced by another gene. e.g hair production gene epistatic to hair colour gene

Question 6

What’s a recombinant ?

Answer 6

A gamete with allele combinations differing from their parents

Question 7

What is BLUP and what are the advantages?

Answer 7

BLUP = Best Linear Unbiased Prediction.

• optimally weights different information sources
• allows Estimated breeding values (EBVs) to be compared between herds
• accounts for non random mating, selection and culling

Question 8

What’s Phenotypic, Genomic and Environmental correlations?

Answer 8

Phenotypic - how measured values of two traits on same group may vary

Genomic - how EBV of 2 traits measured on same group may vary

Environmental - how environmental effects of traits measured on the same group may vary

Question 9

What’s Predicted transmitting ability?

Answer 9

PTA is average genetic value for a given trait that an animal transmits to its offspring

Question 10

What’s genomic selection and how is it carried out?

Answer 10

Selection based on many markers spread across the genome.
Method: 1. genotype of proven bull with reliable Estimated breeding values(EBVs) recorded. markers that effect EBVs are found and calculate the markers effect on each trait
2. Genotype selection of individuals. GEBV calculated and animals with highest GEBV selected

Question 11

What are the advantages of genomic selection?

Answer 11

• Higher success rare to get top bulls
• lower costs for tests proofs
• shorter generation interval