4 Mammalian Nutrition

Question 1

What is the equation for quantitative traits?

Answer 1

P = G + E (Phenotype = Genotype + Environment)

Question 1

What types of genes contribute to genotypic variation?

Answer 1

Nuclear genes, mitochondrial genes, and gene interactions

Question 2

Name two Mendelian traits in dairy cattle.

Answer 2

Polledness, β-casein

Question 3

List three polygenic traits in dairy cattle.

Answer 3

Milk yield, fertility, longevity (others: ease of calving, milk fat yield)

Question 4

Name two health-related traits in dairy cattle.

Answer 4

Milk fever, mastitis (others: ketosis, metritis, displaced abomasum)

Question 5

What does QTL stand for?

Answer 5

Quantitative Trait Loci

Question 6

What is a major factor in genetic progress in livestock?

Answer 6

Sire selection

Question 7

List three applications of genome manipulation in livestock.

Answer 7

Disease-resistant breeds, food safety, vaccine production (others: sex determination, mutation monitoring, biodiversity studies)

Question 8

What is transgenesis?

Answer 8

Direct genetic manipulation to introduce new traits

Question 8

How can gene manipulation improve productivity?

Answer 8

By increasing yield and developing disease-resistant breeds

Question 9

Name three gene delivery methods.

Answer 9

Microinjection, electroporation, viral vectors

Question 10

What is microinjection?

Answer 10

Direct DNA insertion into a fertilized egg

Question 11

What is electroporation used for?

Answer 11

Introducing large DNA plasmids into zygotes using electrical pulses

Question 11

How do viral vectors deliver genes?

Answer 11

Via viruses like retroviruses and adenoviruses

Question 12

What is a key feature of retroviruses in gene therapy?

Answer 12

They integrate RNA into host DNA using reverse transcriptase

Question 13

What is a limitation of retroviruses?

Answer 13

Limited gene capacity (~8000 base pairs)

Question 14

What is the main use of adenoviruses in gene delivery?

Answer 14

For non-dividing cells; safe for in vivo gene therapy

Question 15

What causes ADA-SCID?

Answer 15

Deficiency in adenosine deaminase leading to toxic deoxyadenosine buildup

Question 16

What is one gene therapy treatment for ADA-SCID?

Answer 16

Inserting a functional ADA gene into hematopoietic stem cells

Question 17

What is the first step in ADA gene therapy?

Answer 17

Stem cell harvest from bone marrow

Question 18

What does SCNT stand for?

Answer 18

Somatic Cell Nuclear Transfer

Question 19

What is SMGT?

Answer 19

Sperm-Mediated Gene Transfer — sperm binds and internalizes foreign DNA

Question 20

What is the difference between gene knockout and knockdown?

Answer 20

Knockout eliminates a gene; knockdown reduces gene expression

Question 20

Why is CRISPR-Cas9 revolutionary?

Answer 20

High precision, efficiency, and versatility in gene editing

Question 21

What is the goal of inserting the casein gene in cows?

Answer 21

Increase cheese yield and calcium content

Question 22

What causes milk allergy in humans?

Answer 22

Beta-lactoglobulin (BLG) protein

Question 23

What tool is used to produce hypoallergenic milk?

Answer 23

CRISPR-Cas9 to knockout the BLG gene

Question 24

What is the first step in BLG gene knockout?

Answer 24

dentify the BLG gene

Question 25

What is the final step in producing BLG-free milk?

Answer 25

Verify milk production from transgenic cows

Question 26

How can gene editing improve growth in livestock?

Answer 26

Editing the myostatin gene for increased muscle mass

Question 27

How are GM animals used in drug development?

Answer 27

To produce pharmaceuticals

Question 28

How can gene editing help the environment?

Answer 28

By engineering organisms for environmental remediation

Question 29

What are three goals driving advances in dairy genetics?

Answer 29

Sustainability, health, and consumer preference

Question 30

Why is genetic diversity research important in livestock?

Answer 30

To enhance applications of dairy products