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There are two distinctive mapping approaches used in the field of genome mapping: genetic maps (also known as linkage maps) [7] and physical maps. [3] While both maps are a collection of genetic markers and gene loci, [8] genetic maps' distances are based on the genetic linkage information, while physical maps use actual physical distances usually measured in number of base pairs.
One utility of this approach is that it allows one to obtain values for distances in genetic mapping units directly from recombination fractions, as map distances cannot typically be obtained from empirical experiments. [1] The simplest mapping function is the Morgan Mapping Function, eponymously devised by Thomas Hunt Morgan.
Chromosomes display a banded pattern when treated with some stains. Bands are alternating light and dark stripes that appear along the lengths of chromosomes. Unique banding patterns are used to identify chromosomes and to diagnose chromosomal aberrations, including chromosome breakage, loss, duplication, translocation or inverted segments.
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms. This number, along with the visual appearance of the chromosome, is known as the karyotype , [ 1 ] [ 2 ] [ 3 ] and can be found by looking at the chromosomes through a microscope .
In genetics, a centimorgan (abbreviated cM) or map unit (m.u.) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers ) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.
The alleles on the chromosome form a linkage group due to their tendency to form together into gametes. The distance between the genes (map units) are equal to the percentage of crossing-over events that occurs between different alleles. This diagram is also based on the findings of Thomas Hunt Morgan in his Drosophila cross.
A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be observed.
The online calculation returns as a result a *.csv table with pairwise F ST or Φ ST (R ST) values plus p-values as a test for significance (10,000 permutations). In addition, an MDS plot is generated to illustrate the genetic distance between the analyzed populations graphically. The program shows the references for the selected population ...