selection via DNA in lifestock

Question 1

what is SNP

Answer 1

single nucleotide polymorphism - variation in the DNA
- may be close to the gene or marker
- actual causative mutation

Question 2

what is linkage?

Answer 2

recombination (crossover) more likely between gene mutation and marker
marker is segregating with the trait or mutation

Question 3

what is a linkage test

Answer 3

• biallelic markers in or close to the mutation
  only need to test the individual
• multiallelic markers near mutation - need to test parents

Question 4

what is a PCR

Answer 4

polymerase chain reaction
small starting material to amplify DNA
denature using heat - adding primer to denature again
DNA polymerase extends the sequence repeated 30 times

Question 5

where does to DNA extraction come from in for PCR

Answer 5

hair roots, straws of semen, blood, embryo, milk and tooth pulp

Question 6

what is the central dogma of DNA

Answer 6

DNA- DNA replication - transcription - mRNA (rns replication) - translation - protein

Question 7

how is a protein made!

Answer 7

DNA: double stranded - transcription of coding genes
RNA: single stranded - splicing introns leaving the exons
messenger RNA - translation
amino acid chain - folding
protien

Question 8

what is cDNA used for

Answer 8

for finding mutations
comes from tissues where gene is expressed - 4 PCRs

Question 9

what is important in amino acid changes?

Answer 9

• check if amino acid is changed
• not all mutations have functional effect
• STOP codon is always significant
• cysteine changes usuallu dignificant
• amino acids are in 4 groups

Question 10

what is a silent mutation?

Answer 10

third position of codon often effect
but doesnt change the amino acid

Question 11

what is a missense mutation

Answer 11

amino acid change
impaires or abolishes protein function

Question 12

what is a leptin mutation

Answer 12

a type of missense mutation
fat deposition that changes ariginine (basic) to cysteine (polar) - making sulfide bridges
effects proteins and function

Question 13

what is the fishy egg taint

Answer 13

FMO3 detoxifying liver enzyme
A to T in SNP exon 7
causes thr to ser at aa 329 (t329s) - both polat
loss of enzyme function

Question 14

what is a nonsense mutation

Answer 14

change in the nucleotide results in amino acid change to a STOP codon
- pre mature STOP codon causes a truncated protein

Question 15

what is APAF1?

Answer 15

holstein bull - one of the most bulls in population today 14%
- introduced a recessive mutation in APAF1 gene to holstein population
causes embryonic and fetal mortalilty
c-t changing glutamine to stop

Question 16

what is a frameshift mutation?

Answer 16

insertion or deletion of nucleotides
casues a frameshift in the DNA sequence
pre mature stop codon - truncated protein

Question 17

what is bulldog dwarfism

Answer 17

gene: aggrecan (ACAN)
mutation results in premature stop codon at position 914 (normally 2327 aa)
two copies results in dealth
single copy results in dwarfism

Question 18

what is a causation mutation:

Answer 18

inframe insertion of deletion
3 in or 3 out

Question 19

what is double muscling

Answer 19

gene myostatin (GDF8)
muscular hypertrophy or double muscling especially in hindquarters
reduced fat (body fat and intramuscular)
different mutationc depending on the breed
- autosomal recessive
- chromosome 2

Question 20

what happens when a mutation is not in the coding sequence?

Answer 20

• mutation occurs in a regulatory region ( turn on a gene and cause a protein to be produced in the wrong place or at the wrong time - reduce or eliminate the production of an important protein when it is needed)
• mutation in spice site(mRNA is not sliced correctly)
• mutation in an enhancer or suppressor region (reduce or increase the amount of protein)

Question 21

what are AI sires tested for in holsteins

Answer 21

disease and desirable traits

Question 22

what are purebreds tested for

Answer 22

colour genotype
polled genotype
leptin genotype
genetic abnormalities

Question 23

what are chickens tested for

Answer 23

FMO3 to remove egg taint

Question 24

what are pigs tested for

Answer 24

coat colour (MC1R - red/black
Kit don white and belt
EDNRB spotting)
litter size - estrogen receptor
weight gain
fat content
meat quality - rendement napole (RN) - dominant mutation, meat is pale and soft

Question 25

what is PSS

Answer 25

porcine stress syndrome
- malignant hyperthermia or transport myopathy
- rapid death of animal during transport
- triggered by stress, excitement, anesthetics (halothane)
meat quality is low - PSE
ryanodine receptor gene in calcium channel pathway
T-C at nucleotide position
restrition enzyme - HinPI

Question 26

what is mulefoot

Answer 26

inherited as a autosomal recessive trait with variable penetrance in different cattle breeds
mutations in low density lipoprotein receptor-related protein 4 gene

Question 27

what is BLAD

Answer 27

bovine leukocyte adhesion deficiency
protein needed for white blood cells - without recurrant bacterial infections ulcers and poor teeth, stunted growth
recessive mutation in CD18 gene
unthrifty sickly - calves die

Question 28

what is kappa casein

Answer 28

effects curd properties in milk
important for soft cheese production like brie
BB desirable AA undesirable

Question 29

what is a changeling

Answer 29

calf is born red but coat colour changes to black usually within 3-6 months