Why does strand slippage occur?
Why does strand slippage occur?
Slipped Strand Mispairing (Polymerase Slippage) In areas with repetitive sequences, the polymerase may reassociate with the template strand in a position one or two repeats ahead or behind where it left off (Figure 9.3).
What does DNA slippage cause?
Replication slippage or slipped-strand mispairing involves the misalignment of DNA strands during the replication of repeated DNA sequences, and can lead to genetic rearrangements such as microsatellite instability.
What is slipped DNA?
Slipped strand DNA structures are formed when complementary strands comprising direct repeats pair in a misaligned, or slipped, fashion along the DNA helix axis.
How is replication slippage fixed?
When strand slippage occurs during DNA replication, a DNA strand may loop out, resulting in the addition or deletion of a nucleotide on the newly-synthesized strand. Again, most of these spontaneous errors are corrected by DNA repair processes.
What is the result of slipped strand Mispairing?
Slipped strand mispairing (SSM), (also known as replication slippage), is a mutation process which occurs during DNA replication. It involves denaturation and displacement of the DNA strands, resulting in mispairing of the complementary bases.
Why does forward slippage lead to deletion?
When the polymerase slips forward (B), it skips one of the template GTA repeats, with only three repeats copied into the newly synthesized DNA strand (i.e., deletion of one repeat). Correspondingly, when the polymerase slips backward (C), it copies an extra repeat into the newly synthesized DNA strand.
What is backward slippage?
(A) Slippage of the DNA polymerase and the nascent strand backwards on the template strand would result in the formation of structures containing an excess of repeats on the nascent strand, resulting in expansion products.
What means slippage?
Slippage refers to the difference between the expected price of a trade and the price at which the trade is executed. Slippage can occur at any time but is most prevalent during periods of higher volatility when market orders are used.
What do you mean by Slipped strand mispairing?
Key Terms. Slipped strand mispairing: a process that produces mispairing off short repeat sequences between the mother and daughter strand during DNA synthesis. Slipped strand mispairing (SSM) is a process that produces mispairing of short repeat sequences between the mother and daughter strand during DNA synthesis.
When does Slipped strand mispairing occur in DNA synthesis?
Slipped strand mispairing (SSM) is a process that produces mispairing of short repeat sequences between the mother and daughter strand during DNA synthesis.
Why are long tandem repeats common in Slipped strand mispairing?
We propose that slipped-strand mispairing events, in concert with unequal crossing-over, can readily account for all of these features. The frequent occurrence of long tandem repeats of particular motifs (polypyrimidine and poly-CA tracts) appears to result from nonrandom patterns of nucleotide substitution.
How does SSM affect the binding of regulatory proteins?
SSM induces transcriptional regulation is by changing the short repeat sequences located outside the promoter. If there is a change in the short repeat sequence it can affect the binding of a regulatory protein, such as an activator or repressor.
Why does strand slippage occur? Slipped Strand Mispairing (Polymerase Slippage) In areas with repetitive sequences, the polymerase may reassociate with the template strand in a position one or two repeats ahead or behind where it left off (Figure 9.3). What does DNA slippage cause? Replication slippage or slipped-strand mispairing involves the misalignment of DNA strands…