Unit 3 Exam lecture 17 Flashcards
What is a mutation that does not change the function of the protein
neutral mutation
What mutation causes complete or partial absence of normal protein function
loss of function mutation
what mutation produces an entirely new protein that may have an unrelated function from its origin
gain of function mutation
What are suppressor mutations
restore non mutated function
the number of copies in a tandem repeat (micro-satellite) correlates with what
the severity of the disease
Microsatellites/tandem repeats can affect the protein or
be located in trans
Myotonic dystrophy is an example of what type of genetic disease
tandem repeats
what are the two genes linked to myotonic dystrophy
myotonin protein kinase and ZNF9, and both contain repeat sequences
calculations of mutation rates are affected by
- frequency with which DNA mutates
- probability of repair
- Probability that mutation will be recognized and recorded
Are mutation rates constant within the genome
yes they are and they have an equal likelyhood of happening anywhere in the genome due to mistakes in DNA polymerase
What happens next after muations happen
beneficial mutations stay, harmful die out, neutral have no effect
What are the two classes of DNA mutations
internal factors (random error in DNA pol) and external factors (exposure to mutagenic compounds)
what is a tautomeric shift
where the positions of protons on the nitrogenous bases change and allow allow misspriming (anomalous base paring)
what is the main example of a spontaneous chemical change
depurination
what is the overall process and results of depurination
- loss of a purine (apurinic site)
- strand separation
- A incorporated into complementary new strand
- Old strand still has gap
- Strand separation
- starts cycle of A being incorporated into complementary new strand over and over
dislodging electrons by radiation leads to formation of
free radicals and thymine dimers
What are the steps of mismatch repair enzymes
- detection
- excision (DNA repair endonuclease)
- Polymerization
- ligation
How do transposable elements cause mutations
inserting themselves within genes or by promoting rearrangements
How do transposable elements cause rearrangements
promoting non homologous recombination due to missalinement at metaphase plate
What is the process of a transposable element being inserted into genome
- staggared cuts made by transposase
- insertion of transposable element
- staggard cuts filled in by DNA pol for flanking direct repeats
End of most transposable elements are what
terminal inverted repeats
What would the complementary inverted repeat be for TAGCGT on bottom left of transposable element
Top right would be TGCGAT
What would the complementary flanking direct repeat be for ACGTT on the bottom left of the transposable element
bottom right would be ACGTT
transposase does what
makes staggard breaks in DNA for transposon insertion
Two classes of transposable elements are
class 1 retrotransposons and class 2 DNA transposons
Lines and sines are what specifically
class 1 retrotransposons
DNA transposons are what class and use what mechanisms
Class 2 and use EITHER copy paste or cut and paste
What is the process of a retrotransposon making a new copy and inserting
- Retrotransposon sequence transcribed to RNA
- undergoes reverse transcription = double sided DNA
- staggered cuts
- insertion of new transposon
- replication fills in flanking direct repeats
What is the genetics of black grapes
simply has gene regulating the synthesis of anthocyanin pigments (black)
What is the genetics of white grapes
have Gret 1 retrotransposon inserted near anthocyanin gene that disrupts anthocyanin synthesis (white)
What is the genetics of red grapes
second mutation where most of Gret 1 retrotransposon is removed but a piece is left behind partially restoring anthocyanin (red)
What is the retrotransposon that causes loss of pigment in grapes
Gret1
What are the two transposable elements in Maize
Ds and Ac
what is significant about Ds transposon
lost its transposes so requires Ac to move
A Cc genotype in maize with no transposon insertion gives what color
purple kernels
A cc genotype in maize with no transposon insertion gives what color
white kernels
A Cc genotype with the Ds transposon integrated into the C allele causes what genotypic and phenotypic effects
conversion of Cc to Ctc stopping transcription of C so you will only have c which means yellow kernel
What happens if the Ds transposon is removed from the Ctc gene
get mix of purple and white in corn depending on how early transposition occurred
Sleeping beauty is what
synthetic transposable element
How is sleeping beauty made
components of multiple different transposable elements from multiple different organisms
Insertion of SB into Slc16a10 in mice increased
type 1 diabetes in mice
