selection via DNA in lifestock Flashcards
what is SNP
single nucleotide polymorphism - variation in the DNA
- may be close to the gene or marker
- actual causative mutation
what is linkage?
recombination (crossover) more likely between gene mutation and marker
marker is segregating with the trait or mutation
what is a linkage test
- biallelic markers in or close to the mutation
only need to test the individual - multiallelic markers near mutation - need to test parents
what is a PCR
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
where does to DNA extraction come from in for PCR
hair roots, straws of semen, blood, embryo, milk and tooth pulp
what is the central dogma of DNA
DNA- DNA replication - transcription - mRNA (rns replication) - translation - protein
how is a protein made!
DNA: double stranded - transcription of coding genes
RNA: single stranded - splicing introns leaving the exons
messenger RNA - translation
amino acid chain - folding
protien
what is cDNA used for
for finding mutations
comes from tissues where gene is expressed - 4 PCRs
what is important in amino acid changes?
- 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
what is a silent mutation?
third position of codon often effect
but doesnt change the amino acid
what is a missense mutation
amino acid change
impaires or abolishes protein function
what is a leptin mutation
a type of missense mutation
fat deposition that changes ariginine (basic) to cysteine (polar) - making sulfide bridges
effects proteins and function
what is the fishy egg taint
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
what is a nonsense mutation
change in the nucleotide results in amino acid change to a STOP codon
- pre mature STOP codon causes a truncated protein
what is APAF1?
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
what is a frameshift mutation?
insertion or deletion of nucleotides
casues a frameshift in the DNA sequence
pre mature stop codon - truncated protein
what is bulldog dwarfism
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
what is a causation mutation:
inframe insertion of deletion
3 in or 3 out
what is double muscling
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
what happens when a mutation is not in the coding sequence?
- 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)
what are AI sires tested for in holsteins
disease and desirable traits
what are purebreds tested for
colour genotype
polled genotype
leptin genotype
genetic abnormalities
what are chickens tested for
FMO3 to remove egg taint
what are pigs tested for
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
