Polymorphisms, DNA sequences

Microsatellite repeat markers—Highly polymorphic DNA sequences of short repeats generally comprising <6... 

Electrochemical biosensors were developed for detection and discrimination of either target DNA sequence or single nucleotide polymorphisms. DNA sequence detections have various applications such as detection of target genes, discrimination and classification of various organisms and also detection of genetic based disorders. 

Polymorphism describes a naturally occurring variation in the DNA sequence among individuals which leads to the occurrence of two or more allelic forms of a gene. 

DNA sequences as short as 50-100 bp and as long as 10 kb can be amplified. Twenty cycles provide an amplification of 10 and 30 cycles of 10. The PCR allows the DNA in a single cell, hair follicle, or spermatozoon to be amplified and analyzed. Thus, the applications of PCR to forensic medicine are obvious. The PCR is also used (1) to detect Infectious agents, especially latent viruses (2) to make prenatal genetic diagnoses (3) to detect allelic polymorphisms (4) to establish precise tissue types for transplants and (5) to study... 

There is a normal variation of DNA sequence just as is true of more obvious aspects of human structute. Variations of DNA sequence, polymorphisms, occur approximately once in evety 500 nucleotides, or about 10 times per genome. There are without doubt deletions and insertions of DNA as well as single-base substitutions. In healthy people, these alterations obviously occur in noncoding regions of DNA or at sites that cause no change in function of the encoded protein. This heritable polymorphism of DNA structure can be associated with certain diseases within a large kindred and can be used to search for the specific gene involved, as is illustrated below. It can also be used in a variety of applications in forensic medicine. 

The differences in DNA sequence cited above can result in variations of restriction sites and thus in the length of restriction fragments. An inherited difference in the pattern of restriction (eg, a DNA variation occurring in more than 1% of the general population) is known as a restriction fragment length polymorphism,... 

Smeraldi, E., Zanardi, R. et al. (1998). Polymorphism within the promoter of the serotonin transporter gene and antidepressant efficacy of fluvoxamine. Mol. Psychiatry, 3(6), 508-11. Wang, S. L., Huang, J. D. et al. (1993). Molecular basis of genetic variation in debrisoquin hydroxylation in Chinese subjects polymorphism in RFLP and DNA sequence of CYP2D6. Clin. Pharmacol. Ther., 53(4), 410-18. 

Tautz, D. (1989) Hypervariability of simple sequences as a general source for polymorphic DNA markers. Nucleic Acids Research 17, 6463-6471. 

Wu, Z., Nagano, I. and Takahashi, Y. (1998) The detection of Trichinella with polymerase chain reaction (PCR) primers constructed using sequences of random amplified polymorphic DNA (RAPD) or sequences of complementary DNA encoding excretory-secretory (E-S) glycoproteins. Parasitology 117, 173-183. 

Mutation Permanent change in DNA sequence that will be heritable. Common mutations are also called polymorphisms (see polymorphism). 

Scanning electron microscopy, light microscopy, and confocal laser scanning microscopy together with FISH Randomly amplified polymorphic DNA (RAPD), Enterobacterial repetitive intergenic consensus sequence (ERIC-PCR)... 

There is a diversity of opinion regarding definitions and benefits of pharmacogenetics and pharmacogenomics.1 3 For example, pharmacogenetics is often considered to be the study of inter-individual variations in DNA sequence related to drug absorption and disposition (pharmacokinetics, PK) or drug action (pharmacodynamics, PD). Polymorphic variation in the genes that encode the functions of transporters,... 

Single nucleotide polymorphisms (SNPs) are DNA sequence variations among individuals. Research is under way to hnd out about specihc SNPs (or sets of SNPs) that are associated with various medical conditions and to study the differences in SNP patterns among various human populations. It is hoped that knowledge of SNPs will improve medical treatment by enabling prediction of disease risk and response to therapies. 

Single nucleotide polymorphisms (SNPs). These single-base polymorphisms can be assayed by DNA sequencing or through the use of DNA chips (see Chapter 6). 

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