Examples of DNA sequencing in the following topics:
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- Sanger sequencing, also known as chain-termination sequencing, refers to a method of DNA sequencing developed by Frederick Sanger in 1977.
- The DNA bands may then be visualized by autoradiography or UV light and the DNA sequence can be directly read off the X-ray film or gel image.
- Chain-termination methods have greatly simplified DNA sequencing.
- Automated DNA-sequencing instruments (DNA sequencers) can sequence up to 384 DNA samples in a single batch (run) in up to 24 runs a day.
- The four DNA bases are represented by different colours which are interpreted by the software to give the DNA sequence above.
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- DNA sequencing techniques are used to determine the order of nucleotides (A,T,C,G) in a DNA molecule.
- However, until the 1990s, the sequencing of DNA was a relatively expensive and long process.
- A Sanger sequencing reaction is just a modified in vitro DNA replication reaction.
- As such the following components are needed: template DNA (which will the be DNA whose sequence will be determined), DNA Polymerase to catalyze the replication reactions, a primer that basepairs prior to the portion of the DNA you want to sequence, dNTPs, and ddNTPs.
- From the order of fragments formed, the DNA sequence can be read.
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- Whole-genome DNA-binding analysis is a powerful tool for analyzing epigenetic modifications and DNA sequences bound to regulatory proteins.
- Genomic DNA sequences are being determined at an increasingly rapid pace.
- This has created a need for more efficient techniques to determine which parts of these sequences are bound in-vivo by the proteins controlling processes; such as gene expression, DNA replication and chromosomal mechanics.
- A whole-genome approach was established to identify and characterize such DNA sequences.
- Usually, total DNA before IP (input DNA) is used as hybridization control.
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- Mutations are accidental changes in a genomic sequence of DNA; this includes the DNA sequence of a cell's genome or the DNA or RNA sequence.
- In molecular biology and genetics, mutations are accidental changes in a genomic sequence of DNA: the DNA sequence of a cell's genome or the DNA or RNA sequence in some viruses.
- These random sequences can be defined as sudden and spontaneous changes in the cell.
- In general, this form of mutagenesis requires that the wild type gene sequence be known.
- The basic procedure requires the synthesis of a short DNA primer.
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- Noncoding DNA are sequences of DNA that do not encode protein sequences but can be transcribed to produce important regulatory molecules.
- In genomics and related disciplines, noncoding DNA sequences are components of an organism's DNA that do not encode protein sequences.
- However, many types of noncoding DNA sequences do have important biological functions, including the transcriptional and translational regulation of protein-coding sequences, origins of DNA replication, centromeres, telomeres, scaffold attachment regions (SARs), genes for functional RNAs, and many others.
- Other noncoding sequences have likely, but as-yet undetermined, functions.
- More than 98% of the human genome does not encode protein sequences, including most sequences within introns and most intergenic DNA.
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- An insertion sequence (also known as an IS, an insertion sequence element, or an IS element) is a short DNA sequence that acts as a simple transposable element.
- Although insertion sequences are usually discussed in the context of prokaryotic genomes, certain eukaryotic DNA sequences belonging to the family of Tc1/mariner transposable elements may be considered to be insertion sequences.
- However, when a target sequence has multiple genomic locations, the variously-sized DNA circles formed are difficult to amplify simultaneously.
- Vectorette PCR (vPCR) is another method used to amplify unknown sequences flanking a characterized DNA fragment.
- It involves cutting genomic DNAs with a restriction enzyme, ligating vectorettes to the ends, and amplifying the flanking sequences of a known sequence using primers derived from the known sequence along with a vectorette primer.
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- In the shotgun sequencing method, several copies of a DNA fragment are cut randomly into many smaller pieces (somewhat like what happens to a round shot cartridge when fired from a shotgun).
- By matching overlapping sequences at the end of each fragment, the entire DNA sequence can be reformed.
- This is the principle behind reconstructing entire DNA sequences using shotgun sequencing.
- Since 2005, automated sequencing techniques used by laboratories are under the umbrella of next-generation sequencing, which is a group of automated techniques used for rapid DNA sequencing.
- When a dideoxynucleotide is incorporated into a DNA strand, DNA synthesis stops.
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- Slipped strand mispairing (SSM) is a process that produces mispairing of short repeat sequences 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.
- This RecA-independent mechanism can transpire during either DNA replication or DNA repair and can be on the leading or lagging strand and can result in an increase or decrease in the number of short repeat sequences.
- The short repeat sequences are 1 to 7 nucleotides and can be homogeneous or heterogeneous repetitive DNA sequences.
- Start (ATG) is the start codon in which the ribosome initiates translation of nucleotide sequence into amino acids, and (-10 -35) is the promoter which is the binding site for the RNAP to initiate transcription of DNA into RNA.
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- If the sequence of one strand is AATTGGCC, the complementary strand would have the sequence TTAACCGG.
- During DNA replication, each strand is copied, resulting in a daughter DNA double helix containing one parental DNA strand and a newly synthesized strand.
- A mutation is a change in the sequence of the nitrogen bases.
- For example, in the sequence AATTGGCC, a mutation may cause the second T to change to a G.
- Most of the time when this happens the DNA is able to fix itself and return the original base to the sequence.
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- In prokaryotes, three main types of polymerases are known: DNA pol I, DNA pol II, and DNA pol III.
- DNA pol III is the enzyme required for DNA synthesis; DNA pol I and DNA pol II are primarily required for repair.
- There are specific nucleotide sequences called origins of replication where replication begins.
- In E. coli, which has a single origin of replication on its one chromosome (as do most prokaryotes), it is approximately 245 base pairs long and is rich in AT sequences.
- DNA polymerase I replaces the RNA primer with DNA.