Linkage Disequilibrium

Genes support the molecular basis of phenotypic diversity among individuals. Identification of the location of genes by gene mapping can reveal evolutionary principles leading to phenotypic variation. In this practice, we correlated 10 simple sequence length polymorphism (SSLP) markers with 3 phenotypes to identify possible associations between markers and specific phenotypes in Arabidopsis thaliana It was. These three phenotypes are whether the plants show flowering, whether cell death is observed in plants, and finally the rosette diameter.

Linkage disequilibrium is a measure of the association between alleles of two different genes. If there are more than two alleles found in the organism than expected, the allele is in linkage disequilibrium. If there are two loci (A and B) in the organism and two alleles (A1, A2, B1 and B2) in these loci, linkage disequilibrium (D) is taken as D = f (A1B1) Is calculated. * f (A 2 B 2) - f (A 1 B 2) * f (A 2 B 1) (where f (X) is the frequency of X in the population). D varies from -1 / 4 to 1/4, the greater the deviation from zero the larger the connection. This marker is the result of allele numbering only. Linkage disequilibrium can be the result of genetic proximity. Alternatively, if several allele combinations work well as a team, it can be maintained by natural selection.

Natural selection preserves linkage disequilibrium between alleles of color and pattern of Papilio memnon Among these moths there are genes that determine the shape of the wing. One allele at this location becomes a moth with a tail; the other allele code is a moth that is not captured. There is another gene that determines whether the wings are bright or dark. Therefore, there are four possible kinds of moths. Bright colored moth with or without a tail, black moth with or without a tail. When moths are brought to the laboratory and breed, we can produce all four kinds. However, only two kinds of garls were discovered in the wild. It is a bright color gauge with a tail and a dark gauge without a tail. Maintain non-random association through natural selection. A bright tail moth imitates an unpleasant pattern of seeds. The deformation of the dark is mysterious. The other two combinations are neither imitating nor mysterious, and are eaten immediately by birds.

The power of the association map depends on the mismatch of the links between traits. Gamete imbalance is also known as the gametophase imbalance and is defined as the inheritance of two alleles on the same or different chromosomes that are more likely than chance to be expected. The second definition of LD is also defined as a nonrandom association of alleles at more than one locus, which increases or decreases the frequency of haplotypes in the population in random combinations of alleles at different loci. In a series of generations, there was only a correlation between QTLs that affect traits in a randomized crossmatch and molecular markers closely related to QTL (Mackay and Powell 2007).