Genetic marker
A genetic marker is a
Background
For many years, gene mapping was limited to identifying organisms by traditional phenotypes markers. This included genes that encoded easily observable characteristics such as blood types or seed shapes. The insufficient number of these types of characteristics in several organisms limited the mapping efforts that could be done. This prompted the development of gene markers which could identify genetic characteristics that are not readily observable in organisms (such as protein variation).[1]
Types
Some commonly used types of genetic markers are:
- RFLP (or Restriction fragment length polymorphism)
- SSLP (or Simple sequence length polymorphism)
- AFLP (or Amplified fragment length polymorphism)
- RAPD (or Random amplification of polymorphic DNA)
- VNTR (or Variable number tandem repeat)
- SSCP (or Single-strand conformation polymorphism)
- SSR Simple sequence repeat)[2]
- SNP (or Single nucleotide polymorphism)
- STR (or Short tandem repeat)
- SFP (or Single feature polymorphism)
- DArT (or Diversity Arrays Technology)
- RAD markers (or Restriction site associated DNA markers)
- STS (using Sequence-tagged sites)[2]
Molecular genetic markers can be divided into two classes: a) biochemical markers which detect variation at the gene product level such as changes in proteins and amino acids and b) molecular markers which detect variation at the DNA level such as nucleotide changes: deletion, duplication, inversion and/or insertion. Markers can exhibit two modes of inheritance, i.e. dominant/recessive or co-dominant. If the genetic pattern of homo-zygotes can be distinguished from that of hetero-zygotes, then a marker is said to be co-dominant. Generally co-dominant markers are more informative than the dominant markers.[3]
Uses
Genetic markers can be used to study the relationship between an
Genetic markers are employed in genealogical DNA testing for genetic genealogy to determine genetic distance between individuals or populations. Uniparental markers (on mitochondrial or Y chromosomal DNA) are studied for assessing maternal or paternal lineages. Autosomal markers are used for all ancestry.
Genetic markers have to be easily identifiable, associated with a specific
Some of the methods used to study the genome or phylogenetics are RFLP, AFLP, RAPD, SSR. They can be used to create genetic maps of whatever organism is being studied.
There was a debate over what the transmissible agent of
Genetic markers have also been used to measure the genomic response to selection in livestock. Natural and artificial selection leads to a change in the genetic makeup of the cell. The presence of different alleles due to a distorted segregation at the genetic markers is indicative of the difference between selected and non-selected livestock.[5]
See also
- Marker gene
- Molecular marker
- DNA marking
- Eukaryotic chromosome fine structure
- Repeated sequence (DNA)
References
- ISBN 978-1-4641-0946-1.
- ^ ISBN 978-3-030-20728-1.
- ISBN 978-81-322-0958-4.
- ^ Murgia C, Pritchard JK, Kim SY, Fassati A, Weiss RA. Clonal origin and evolution of a transmissible cancer. Cell. 2006 Aug 11;126(3):477-87.
- PMID 12454081.
Further reading
- de Vicente C, Fulton T (2003). Molecular Marker Learning Modules – Vol. 1. IPGRI, Rome, Italy and Institute for Genetic Diversity, Ithaca, New York, USA.[permanent dead link]
- de Vicente C, Fulton T (2004). Molecular Marker Learning Modules – Vol. 2. IPGRI, Rome, Italy and Institute for Genetic Diversity, Ithaca, New York, USA.
- de Vicente C, Glaszmann JC (2006). Molecular Markers for Allele Mining. AMS (Bioversity's Regional Office for the Americas), CIRAD, GCP, IPGRI, M.S. Swaminathan Research Foundation. p. 85. Archived from the original on 2007-12-04. Retrieved 2007-12-12.
- Spooner D, van Treuren R, de Vicente MC (2005). Molecular markers for genebank management. CGN, IPGRI, USDA. p. 126. Archived from the original on 2008-05-03. Retrieved 2007-12-12.
External links
Media related to Genetic markers at Wikimedia Commons