Furthermore, genetic maps are based on Mendelian inheritance patterns whereas physical maps are not directly on Mendelian inheritance patterns. Genome studies use genetic markers located in the chromosomes. To study these markers, they have to be mapped using different techniques. Mendelian genetics is the basis of genetic maps. During the genetic mapping, different traits are studied for many generations and the genes are analyzed using gene linkage and gene association studies.
In contrast, Physical gene maps involve the isolation and characterization of genetic markers physically by extracting it. This is the main difference between genetic map and physical map. Available here 2. Available here. Samanthi Udayangani holds a B. Degree in Plant Science, M. So can vaccines be made with only genome mapping or do you need genome sequencing to create a vaccine? See our Privacy Policy and User Agreement for details. Gene mapping means the mapping of genes to specific locations on chromosomes.
Such maps indicates the positions of genes in the genome and also distance between them. The SlideShare family just got bigger. Home Explore Login Signup. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. Difference between genetic linkage and physical map.
Upcoming SlideShare. Like this presentation? Why not share! Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Next SlideShares. Download Now Download to read offline and view in fullscreen. In these experiments, the two alleles of a particular gene led to either homozygosity or heterozygosity. Additionally, the complicated situations of this simple dominant-recessive rule include incomplete dominance, codominance, etc. Furthermore, his First Law states that alleles segregate randomly while his Second Law states that pairs of alleles segregate independently.
However, in general, chromosomes are the intact units of inheritance and the set of alleles in it will be inherited together, which is partial linkage. Principally, partial linkage explains the behavior of chromosomes in meiosis as described by Thomas Hunt Morgan. Sometimes, all the alleles in the chromosome may not inherit together with the occurrence of crossing-over during meiosis.
In fact, crossing-over is a random event, which can separate two genes on the same chromosome depending on their relative distance. On that account, recombination frequencies can be used to determine the distance between two genes. Hence, a genetic map can be constructed by working out on the recombination frequencies of several pairs of genes. Also, planned breeding in plants and pedigree analysis in humans are the methods to obtain recombination frequencies.
Physical mapping, on the other hand, is the technique used to indicate the physical distance of two genes. Generally, the low resolution of genetic maps due to fewer crossovers as well as their limited accuracy make physical mapping important. Also, it gives the actual distance between markers by means of the number of nucleotides. Basically, the most important forms of physical mapping techniques include restriction mapping, FISH fluorescent in situ hybridization , and STS sequence-tagged sites mapping.
In restriction mapping, restriction sites serve as DNA markers. Of these, polymorphic restriction sites used are a few, but non-polymorphic restriction sites used are numerous.
Generally, the simplest way to construct a restriction map is to compare the fragment sizes produced by the digestion of a DNA molecule with two different restriction enzymes, having different target sequences. However, restriction mapping is more applicable to short DNA fragments with relatively few cut sites. Still, there is a possibility to analyze entire genomes larger than 50 kb by using rare cutters with infrequent cut sites. This article has been posted to your Facebook page via Scitable LearnCast.
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