Marker and Primer
A marker is an identifiable physical location on a chromosome (e.g., restriction enzyme cutting site, gene, minisatellite, microsatellite) whose inheritance can be monitored. Markers can be expressed regions of DNA (genes) or some segment of DNA with no known coding function but whose pattern of inheritance can be determined. It is not normally "designed" unless you have a plasmid which already contains the gene (cDNA) for this specific marker. Another definition of marker in molecular biology is that of a molecular weight marker as a DNA fragment of known size used as a comparison standard in estimating the size of a DNA fragment of unknown size.
A PCR primer, on the other hand, is a short sequence (of RNA or DNA) from which DNA replication can initiate. May be either a synthetic DNA or RNA or a length of RNA synthesized in vivo by primase. A primer is required because most DNA polymerases, enzymes that catalyze the replication of DNA, cannot begin synthesizing a new DNA strand from scratch, but can only add to an existing strand of nucleotides. Normally two sets of primers are used in each PCR reaction, the "forward" and the "reverse" primer which are normally designed to be complementary with the beginning and at the end on the marker of interest to be amplified (but on different strands of the DNA, as replication always go from 5´ to 3´).
Marker and Primer
A marker is an identifiable physical location on a chromosome (e.g., restriction enzyme cutting site, gene, minisatellite, microsatellite) whose inheritance can be monitored. Markers can be expressed regions of DNA (genes) or some segment of DNA with no known coding function but whose pattern of inheritance can be determined. It is not normally "designed" unless you have a plasmid which already contains the gene (cDNA) for this specific marker. Another definition of marker in molecular biology is that of a molecular weight marker as a DNA fragment of known size used as a comparison standard in estimating the size of a DNA fragment of unknown size.
A PCR primer, on the other hand, is a short sequence (of RNA or DNA) from which DNA replication can initiate. May be either a synthetic DNA or RNA or a length of RNA synthesized in vivo by primase. A primer is required because most DNA polymerases, enzymes that catalyze the replication of DNA, cannot begin synthesizing a new DNA strand from scratch, but can only add to an existing strand of nucleotides. Normally two sets of primers are used in each PCR reaction, the "forward" and the "reverse" primer which are normally designed to be complementary with the beginning and at the end on the marker of interest to be amplified (but on different strands of the DNA, as replication always go from 5´ to 3´).
Molecular markers is cutted sequences mixed. Is same meter indicator we use in swimming pool. So after experiment finish (pcr) we compare the size of our pcr product (E. coli toxin gene) with marker to know the size. Marker already prepared in company.
Primers is just short sequence of oligonucleotide (ATCTG) use to be complementary of our target DNA. After link to target DNA another enzyme (polymerase) amplify the DNA. Primers is to small, so not appear in gel electroforesis. If appear you may see at bottom lower than lower the marker.
In medicine or oncology the definition is different.
- Badges
- Science method