Introduce and Explain the Concepts behind Genetic Mapping and How Maps are made.
Genetic mapping refers to the determination of the position of genes on the DNA molecule, which is the plasmid or chromosome and the relative distance between the genes, in physical units or linkage units (Waldron 2016). Having this in mind, the paper will begin by reviewing the basic concepts of genetic mapping and also on how genetic maps are made.
Concepts behind genetic mapping
The basic concept of genetic mapping is that, genes do not separate autonomously. Genes that do not separate autonomously are known as linked. One of the best ways to explain linkage is to examine the DNA of organisms. In this case, we identify that genes that are linked are those that lie on similar chromosome, therefore, they are inherited together (Knagge, Yousef, Winnike, Blankenship, Thomas and Brown 2017).
In addition, genetic mapping is based on the principle of meiosis. Meiosis refers to the creation of haploids from diploid cells. During mapping, the specific portion of meiosis which researchers are most interested on is crossing over that takes place in prophase I. crossing over is significant as it is the one that produces variations in gametes, which is used during genetic mapping as a measure of distance between genes (Kushanov, Pepper and Abdurakhmonov 2016).
How Genetic Maps are Made
In order to make genetic maps, researchers begin by collecting tissues or blood from all the members in a given family of interest. The researchers use laboratory techniques to isolate DNA from the samples they had collected to study on the unique traits only seen in family members. The characteristics found in the chemical bases that structure the DNA are known as markers. Markers do not identify the gene that contain the trait, however, it helps the researchers to identify the location of the gene in the chromosome. In other word, when a given gene is close to the marker, the marker and gene will stay together through the process of recombination, which will be passed to the child from the parent. In this case, if a family member inherits a certain trait, it means that they will also inherit a certain DNA marker, which also means that the gene liable for the trait lies close to the DNA marker. Therefore, the more the DNA markers appear on the genetic map, the more likely that at least one marker will be found close to the trait and the easier the researcher will be able to locate it on the gene (Boutet, Carvalho and Baranger 2016).
In conclusion, genetic mapping, which is also known as linkage mapping gives researchers the opportunity to identify the traits that are passed to the child from the parents, this is based on the concept that, the traits transmitted are linked to the genes. In addition, mapping provides researchers with clues on the chromosomes that contain the gene and the location of the gene on the chromosome. Therefore, genetic mapping is very important in the identification of new genes and their functionality, which is vital in the determination of genes responsible for disorders in human beings.
Boutet, G., Carvalho,. and Baranger, A., 2016. SNP discovery and genetic mapping using genotyping by sequencing of whole genome genomic DNA from a pea RIL population. BMC genomics, 17(1), p.121.
Kushanov, F.N., Pepper,. and Abdurakhmonov, I.Y., 2016. Development, genetic mapping and QTL association of cotton PHYA, PHYB, and HY5-specific CAPS and dCAPS markers. BMC genetics, 17(1), p.141.
Knagge, K., Yousef, G., Winnike, J., Blankenship, K., Thomas, A. and Brown, A., 2017. Relationship in Broccoli Between Genetic Mapping and Small Molecule Profiling Using NMR Spectroscopy. The FASEB Journal, 31(1 Supplement), pp.766-11.
Waldron, D., 2016. CRISp (e) R genetic mapping. Nature Reviews Genetics, 17(7), pp.375-376.