Distinguish among cytogenetic, linkage, and physical mapping.
First of all, we need to understand what mapping in genetics refers to- it is just a procedure to identify the locus of a particular gene and the distances between genes. There are generally two distinct types of maps used in the field of genome mapping, namely, genetic maps or cytogenetic mapping and physical maps.
Genetic mapping is a process to determine which chromosome has which gene and pinpointing where that gene lies on that particular chromosome. Mapping also acts as a method to find which gene is most likely recombine based on the distance between two genes. The distance between two genes is measured in units known as centimorgan. A centimorgan is a distance between genes for which one product of meiosis in one hundred is recombinant. The distant two genes from each other, the more likely they are going to recombine. If it were closer, the opposite would occur.
In physical mapping, there are no definite ways of marking up a specific gene since the mapping does not include any information that concerns traits and functions. Genetic markers can be linked to a physical map by processes like in situ hybridization. The visual appearance of a chromosome when stained and examined under a microscope comes under the umbrella of cytogenetic mapping. There are important visually distinct regions, called light and dark bands, which give each of the chromosomes a unique appearance.
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