Repetitive DNA Part 4 Flashcards
1
Q
Transposition
A
- moves mobile genetic elements between non homologous sites in the genome
1) to different places within one chromosome
2) between 2 chromosomes
2
Q
what is responsible for a large fraction of the evolutionary change in a genome
A
- mobile elements
3
Q
each mobile element contains
A
- an enzyme that mediates its own movement - transposase
- special sites upon which the enzyme acts - to mobilize the transposons
4
Q
transposons
A
- transposable elements
5
Q
mobile genetic elements target site selectivity
A
- have only little target site selectivity therefore move freely throughout the genome
6
Q
transposase acts on specific DNA sequence at the end of transposon
A
- disconnects transposon from flanking DNA
- inserts it into new target DNA site
- no requirement for homology
- most move only rarely
7
Q
3 classes of transposons
A
- DNA transposons
- LTR-containing transposons
- non-LTR retrotransposons (non autonomous retrotransposons)
8
Q
wild type maize
A
- C locus expressed
9
Q
Mutated maize
A
- transposable element ds is inserted into C locus and knocked out its expression
10
Q
reverted maize
A
- Ac acts upon Ds element to jump it out in some cells to restore color
11
Q
which element is more active
A
- Ac element more active than Ds element
12
Q
Ac transposon
A
- has full transposon
- has transposase
- inverted repeats
13
Q
transposase acts on Ds
A
- to move them but they can’t move themselves
14
Q
original mutation
A
- result of transposable element in C gene
- DS
15
Q
another transposable element
A
- Ac = activator
- induces Ds to transpose out of C, causing reversion
