Mutation and chromosomal aberration Flashcards
What are some important principals regarding mutations and chromosomal abberations? ( 4 things G, M, D, M)
- Genes can have different DNA sequences. These varients arise by mutation and are called ALLELES
- Mutations are spontaneous, the raw material of evolution
- Different kinds od mutation affect the function of a gene in different ways
- Most variable traits are the product of many different genes, they have a complex basis.
What are alleles? What are they caused by?
- Different versions of the same gene .
- Keep in mind alleles do not cause mutation, mutations cause alleles.
How do mutations cause alleles?
- if there is a gene and something is missing or gets mutated, it alters the gene creating a new allele resulting in a mutation.
Do mutations happen all the time? How often?
- Mutations happen all the time, they are spontaneous though.
What are some cons of spontaneous mutations? Give an example?
- Spontaneous mutation can cause cancer
- Body makes new cells copying DNA, there can be a mutation to the gene that controls cell division, the cells won’t stop dividing creating a tumor that turns into cancer.
What are phenotypes? ( think of p and think of outside)
What are genotypes? (think of g in gynecologist and think od inside)
- Geno type has to do with DNA
- Phenotype has to do with physical traits.
What is a germline mutation rate? (what is germ referred to in biology)
- How often mutations occur in the DNA of Sperm or eggs
What is the germline mutation rate in humans? ( half, ten nine)
- 0.5 x 10-9 bp per year
What is a human genome, what does it make up?
- The human genome is the complete set of genetic instructions tha make up the human being.
What is the human genome? ( 3 10, 9)
3 x 10 9
How many mutations will your child have if you have you kid on an avg of 25 years old?
Do these affect genes?
- your child will have approx 37 mutations inherited
- The vast majority of these do not affect genes.
Do mutation affect the expression of activity of genes?
No, they do not affect the vast majority if they are silent, occur in non coding regions (introns), or don’t affect critical proteins
What are some important sources of mutations?
- Endogenous
- Exogenous
What does endogenous mean? think of the prefix endo
- DNA Replication errors
- Transposable elements ( retrotransposons)
What does exogenous mean? think of the prefix (exo)
- UV radiation (sunlight; think of skin cancer)
- Ionizing radiation ( x rays)
- Chemical mutagen=s in the environment (food; fungi, carinogenic foods)
How are mutations detected? ( eyes) ( affect), and most obv
- They are detected by their visible traits such as color, shape, and size
- Their affect on the gene product or the protein they produce
- by their DNA
What are some different visible phenotypes
- Round versus wrinkled
-yellow versus green - inflated or pinched pods
- short versus tall
What is the correlation between mutations and A2 Casein milk?
What is the difference between A1 milk and A2 milk ?
- Cows have a protein in milk called beta casein
- Some make A1 milk while other cows make A2 milk
- The difference between A1 milk and A2 milk is that there is a mutation in the cows DNA
Why does the milk mutation with A1 milk and A2 milk matter?
- Some people have a digestion problem with A1 milk
- People have reported that A2 Milk is easier to digest
What is the polymerase chain reaction?
How does it work?
How is it useful?
- look at video of how this works
- PCR is a lab technique that is uses to make smaller copies of DNA. Like making photocopies from a book
- First the DNA is heated so it can de nature and unzip into two strands.
-Primers are added (they are tiny pieces of DNA). They act as starting points to help copy DNA - DNA polymerase helps build new DNA strands and the whole process id repeated.
- This is helpful because it helps gather enough DNA to sample.
How do you visualize DNA change with PCR?
- DNA changes can be visualized with PCR using gel electrophoresis which separated DNA based on SIZE allowing you to see what has been altered
- One would be longer than the other
Summarize how PCR is used to visualize change in DNA + example.
- Overall PCR helps visualize changes by amplifying a specific part of DNA
- If a mutation deletes part of a DNA segment, PCR will produce shorter fragments to fill up the missing part versus the normal one.
- By making copies, it is easier to detect what is missing.
What does it mean that DNA is Antiparallel?
- DNA is antiparallel meaning that the 2 strands that form the helix RUN in opposite directions
- One side if 5’ to 3 ‘ while the other side is 3’ to 5’
PCR Analysis of seedling segregation for the hy4 deletion??
- WT x WT = one full length band no deletions
-Hy4 deletion x Hy4 deletion = only shorter bands ( both copies have deletion
- WT/hy4 x WTxhy4 = 1:2:1 ratio.
25% show full length band
50% shows full length and shorter band
25% shows shorter bands
How do mutations affect the regulatory region?
- mutation affect timing, location, and the amount in regulatory region
How do mutations affect the transcribe region
- it affects the activity of a gene product
What effect do mutations have on gene function? Why?
- Very little effect on gene function
- b/c they produce synonymous changes
What happens with the mutations that do effect gene activity?
- Produce defective proteins ( loss of function)
What gene type are mutations
- they are recessive
What are silent mutations what do they do
- genetic change that doesn’t affect amino acid sequence
- no effect on gene activity bc they change a codon to another that OCDES FOR THE SAME AMINO ACID due to redundancy of the genetic code.
What is Tyrosinase?
It’s an enzyme that plays a key role in melanin production
What is tyrosinases importance?
What does it result in
- Different alleles (versions) of this gene affects how much pigment is made
- This results in different fur colors.
What is the special allele relating to tyrosinase?
What is its importance?
- TYRC
- Only works at cooler parts of the body like nose, toes, feet.
Can sweet corn be produced by many different mutations?
Example of three
- Yes, a variety!
- su, se, sy
What are the 4 D’s regarding variation in chromosome structure?
- Duplication
- Deletion
- Inversion
- Reciprocal Translation
What is duplication?
- Extra copy of segment
What is Deletion
- loss of a segment of DNA
What is inversion
- inverted segment of DNA
What is reciprocal translocation
- exchange between non homologous chromosomes.
Who discovered transposons?
- Barbra Mcclintock
What is the difference between retrotransposons and regular transposons?
- transpososns cut them selves and jump to a new page ( no copy)
- Retrotransposons make a copy and then paste somewhere else in the book
What are transposons a great part of? ( 2 things)
- Humans and plants.
