Cycle 5 Flashcards
Are transposable Elements
Present in plant cells? Do they undergo transposition?
YES
When they do, they can interfere with a gene for example one that is involved in the ____________ of pigment production, and so the pigment is either produced or not produced (that is how u get different colors in the corn or kernel)
biosynthetic pathway
___-____% of human genes contain TEs (up to 1000 per gene)
70-80
TE: In the ______ region
intron
Not interfering with ______
splicing
Most TE are “____” due to inactivating mutations (cannot undergo transposition)
dead
The effect varies from _______ to ______
negligible to disease
Active TEs have evolved to insert into “____ ____” in the genome
safe havens
Genes produce ______ that inhibit jumping
proteins
The host _____ (inactivates) most active TEs
silences
What do transposable Elements do (what happens if they jump)? (2)
-TE lands in non-coding (safe haven) regions
-TE lands in a protein-coding gene:
Insertions can lead to disease-causing mutations (ex: _____ when no one in the family has a history)
hemophilia
HOW?
-Transposable element interferes with factor 8 gene
-This factor produces a protein involved in clotting your blood
L1 (type of TE that goes and inserts itself in the factor 8 gene by a transposition event)
-Therefore clotting gene is not funcitinobale
Insertions can also lead to gene ______
shuffling
HOW?
-Each gene has its own promoter
One promoter can activate more than one gene
Ex: promoter one is specific for Gene 1 and Gene 2, it activities they, promoter two is specific for Gene 3 and Gene 4
When TE lands in the region
Can leave part of its sequence in that original region and jump
The second thing it can do is take part of the sequence with it
OR third, take the entire gene with it
Inference causes nonfunctional protein
If TE is cut and pasted then gene 1 will be in control of the wrong promoter
Promoter determines expression
Gene 1 is now regulated under a different promoter
Now gene is transcribed and translated at the incorrect rate
___ elements cause disease
Most common TE
Has the ability to jump
Alu
List of mechanisms to generate genomic variation
DNA polymerase
Non-homologous End Joining
Slippage
Tautomeric shifts
Transposition
__________ makes errors as it adds bases during DNA synthesis
DNA polymerase
Sloppy mechanisms to repair double-strand breaks caused by ionizing radiation
Non-homologous End Joining
InDel mutation
Forward ______ on the template strand leads to deletion
Backward ______ on synthesized strand leads to insertion
Slippage
Spontaneous shift in the chemical form of nitrogenous bases changes preferential pairing
T and G shift from dominant keto form to rare enol form
A and C shift from domina amino to rare imino form
Tautomeric shifts
Cut/copy and paste transposable elements mostly between genes
More transposable elements are found in larger genomes
Transposition
______ was the first to pioneer how phenotypic expression is a result of different genes or alleles interacting with one another
Gregor Mendel
he used pea plants because (3)
-Fast generation time
-Easy to manipulate the peas
-Didn’t have scientific tools back in the day, relying on the naked eye (observable phenotype)
he concluded:
You need ___ alleles for one trait (mendelian form of inheritance)
2
Most of our inehetricen now are nonmendelian, but in fact, are ______ (many genes give rise to a specific phenotype)
polygenic
_______: The dominant one will express the phenotype
Heterogsyous
At the genetic level, what is the difference between a dominant vs receive allele?
At the DNA level: the sequence is different
______ in DNA means the gene is being transcribed and RnA is being made
Expression
Expression in _____: whatever is happening in the cell, the phenotype being expressed on the organism (color, shape, etc)
phenotype
T/F A recessive allele means it is not being expressed in the cell
FALSE: A recessive allele doesn’t mean it is not being expressed in the cell