Genetic markers, development

S. Rosendhal and J. W. Taylor, Development of multiple genetic markers for studies of genetic variation in arbuscular mycorrhizal fungi using AFLP. Mol. Ecol. 6 821 (1997). 

Atopy is inborn and characterized by genetic markers and increased IgE-antibody concentration. The increased concentration must be accompanied by clinical symptoms of a disease. If only the level of IgE is exceeded, it is not a sign of a disease, however it may forecast developing of the allergy in the future. 

The main risk factor appears to be a genetic susceptibility to the illness. The majority of narcolepsy patients, particularly those with cataplexy, have a genetic marker known as HLA-DQB1 0602. Recent evidence indicates that the key dysfunction in narcolepsy is diminished activity of a newly discovered neurotransmitter known as hypocretin. This new evidence has led to the development of a new diagnostic test for narcolepsy and may ultimately lead to new treatments that act directly on hypocretin systems in the brain. 

Family history is also important. If you have a parent or sibling who has been diagnosed with AD, you are four times more likely to develop the illness. If two close relatives have AD, you are eight times more likely to have AD. This suggests that there may be a genetic, inherited basis for the disease. In fact, genetic studies have revealed that one-third or more cases of AD may be traceable to a genetic marker known as apolipoprotein E4. 

The nondisjunction test developed by Craymer75 involves an X Y translocation stock that is mated to a standard female line with appropriate genetic markers. 

Gupta, R.S., and L. Siminovitch. Genetic markers for quantitative mutagenesis studies in Chinese hamster ovary cells. Characteristics of some recently developed selective systems. Mutat. Res. 69 113-126,... 

Because a library can contain thousands of different clones, it can be difficult to isolate a clone with DNA of specific interest. This is because the majority of cloned DNAs do not contain a readily selectable genetic marker, such as antibiotic resistance, or lead (as discussed earlier) to the production of a foreign protein. Methods to achieve this have been developed and utilize hybridization, immunochemical, and structural techniques. A specific DNA sequence of only several kilobases can be isolated from a genome containing in excess of 106 kilobases. Hybridization requires a radioactive DNA or RNA molecule (a probe) that is complementary (or partially so) to the sequence of the cloned DNA. Immunologic techniques require that the polypeptides coded by the DNAs of interest are available and have specific antigenic properties that allow detection. Structural analysis can also be used when the other techniques are inapplicable. 

Specific reports on applications of this technique for forensic purposes are still scarce. The apparent reason for this slow penetration of CE into forensic genetics is twofold. First, the analysis of genetic markers by CE is not a simple technology, and it must be performed in a specialized laboratory. Second, the field of DNA fragment separation by CE is still being developed methodologically and is not an established technique as compared, for example, to slab gel electrophoresis. Nevertheless, this technique should become widespread in forensic biology in the relatively near future. 

Ribas de Pouplana L, Schimmel P. Aminoacyl-tRNA synthetases potential markers of genetic code development. Trends Biochem. Sci. 2001 26(10) 591-596. 

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