Gene Mapping Significance And Improvements †MyAssignmenthelp.com

Question: Discuss about the Gene Mapping Significance And Improvements. Answer: The technique of gene mapping was first illustrated by Thomas Hunt Morgan in 1911 while studying the genetics of Drosophila. Gene mapping or linkage mapping refers to a representation of recombination frequencies and relative distance between markers loci in homologous chromosomes (Robinson 2013). Significance- Gene maps are essential for providing an avenue to link a trait of particular interest to a specific genetic region in the chromosome. Genetic mapping helps in utilizing a mechanism that tracks the co-segregation of different genetic markers associated with particular traits in a population. Such markers can be utilized in agriculture to improve animal breeds and resistant crops (Morrell, Buckler and Ross-Ibarra 2012). They are used in evolutionary studies to understand the mechanism of diversification of different species. Comparative mapping between or within taxa helps in revealing regions where there is gene order conservation. They locate regions of chromosomal duplication. These maps have huge significance in medicine and help in identification of people who are vulnerable to a host of genetic diseases. They detects carrier in recessive disorders where the affected gene is not directly expressed (Eyre et al. 2012). Microbial genetic maps help in producing energy b y harnessing the power of bacteria and also help researchers to develop environment friendly products. Positional cloning is another application. It has been utilized in isolating maize genes in recent years. Genetic mapping also determines the effect of location on the expression of genes and identifies several factors that affect recombination between genes. These maps also recognize the non-functional pseudogenes and their probable role. Eye pigments- The eye colour pigments in Drosophila are produced by two distinct biochemical pathways: the pteridine pathway (pale blue to yellow to scarlet pigment) and the ommochrome pathway (brown pigment). A large number of genes are associated with the eye colour phenotype. Wild type eye color in Drosophila is red. Several studies have shown the brown pigment to be xanthommatin, which is a member of the ommochrome class, called ommatins. A homozygous recessive mutation in the pteridine pathway that produces the pigment drosopterin will prevent the production of the bright red pignment and results in a dull brown colour (Grant et al. 2016). If there occurs a loss-of-function mutation in the cinnabar gene, responsible for synthesis of brown pigment, the phenotype will be bright red for such homozygous cinnabar mutant flies. Improvements- The original gene mapping approaches were based on single point variations and they failed to detect the developmental changes in traits. Investigation of inherited haplotypes will prove effective in locating the human gene map. However, these haplotypes can fail in incomplete disease penetranceor etiologic heterogeneity (Sun and Wu 2015). Therefore, a functional mapping model (computer programs like MENDEL, VITESSE and LINKAGE) that focuses on statistical framework can be used, which will focus on estimation of the loci related to the disease based on the markers and phenotypes. Thus, it can be concluded that gene mapping techniques are essential for mapping the recombination frequencies between different markers on homologous chromosomes. They are widely used to determine the mutations that occur during meiotic recombination in Drosophila. References Eyre, S., Bowes, J., Diogo, D., Lee, A., Barton, A., Martin, P., Zhernakova, A., Stahl, E., Viatte, S., McAllister, K. and Amos, C.I., 2012. High-density genetic mapping identifies new susceptibility loci for rheumatoid arthritis.Nature genetics,44(12), pp.1336-1340. Grant, P., Maga, T., Loshakov, A., Singhal, R., Wali, A., Nwankwo, J., Baron, K. and Johnson, D., 2016. An eye on trafficking genes: Identification of four eye color mutations in Drosophila.G3: Genes, Genomes, Genetics,6(10), pp.3185-3196. Morrell, P.L., Buckler, E.S. and Ross-Ibarra, J., 2012. Crop genomics: advances and applications.Nature reviews. Genetics,13(2), p.85. Robinson, R., 2013.Gene mapping in laboratory mammals. Springer. Sun, L. and Wu, R., 2015. Mapping complex traits as a dynamic system.Physics of life reviews,13, pp.155-185.