401-Biochemistry Laboratory - Modern Theory and Techniques (2nd Edition)-Rodney F. Modern Theory and Techniques (2nd Edition)-Rodney F.

Personalized medicine refers to medical care that involves genetically screening patients for their likelihood to develop various disorders. Commercial genome screening only involves identifying a consumer's genotype for a few single nucleotide polymorphisms.

Epson Brighter Futures Education Program. A phenotype (such as an illness) is greatly influenced by three factors: genes, gene expression levels, and the environment. The information supplied by personal genomics companies only involves genes and as such is not always indicative of a particular phenotype. Here, we propose a method for developing modular undergraduate laboratories that examine each contributing factor for a single gene. Although each module is suitable as an individual laboratory exercise, every module may be used in the same class to examine a single phenotype of interest, give students a more complete understanding of how a phenotype is produced and allow students to understand the science behind personalized medicine. Companies such as 23andMe, deCODEme, Navigenics, and DNA Direct are currently offering consumers the chance to screen their genomes for genotypes that are strongly correlated with medical conditions [ ].

Typically, this sort of correlation means that the individual with the genotype has an increased chance of expressing the phenotype in question, which is usually a disease. However, drawing such a conclusion is dangerous because the presence of a particular genotype is rarely as sure an indicator of the disease as people like to believe [ ]. A person's environment, genetic background, and the amount of gene expression always factor into any phenotype, including the phenotypes for which personalized genomics companies test. Unfortunately, this fact is frequently forgotten during the pursuit for information of one's genome. Currently, personalized genomics companies only make use of the information that is available for a specific type of genetic variation: the single nucleotide polymorphism (SNP).

A SNP is a variation in one base pair; for example, the substitution of a cytosine where a thymine should be. Four of the most common kinds of genetic variation include SNPs, variable number tandem repeats (VNTRs), copy number variants, and insertions or deletions (indels). Unfortunately, none of these companies offer services beyond determining what kind of SNPs a given individual has. Although raw genomic data are a powerful tool for understanding the roles of genes in everyday life, such data are not all‐important. Three main factors coalesce to give a more accurate picture of how a gene works: gene sequences, gene expression, and the environment.

Download Hp Laserjet 6p Driver Windows 7. For the undergraduate laboratory, polymerase chain reaction (PCR) with gel electrophoresis, quantitative polymerase chain reaction (QPCR), and restriction fragment length polymorphism (RFLP) analysis are the most desirable because of their relatively low cost, ease of use, and ability to provide teaching topics. Gene chips and sequencing, on the other hand, are not as suitable for pedagogic use because of the greater cost of the service and equipment required for these techniques. As differences in an individual's genome have been correlated with some phenotypic traits, QPCR is typically a very effective tool for investigating an individual's genotype. Huntington's disease is an excellent example of the diagnostic power of QPCR because the disease is closely associated with a VNTR [ ].

However, as we just noted, polymorphisms are not the whole story. Gene expression, how often a given transcript is transcribed, is extremely important to consider when attempting to understand the function of a gene. It could be that a given mRNA is produced continuously, at a specific time, or even as a result of environmental stimulus. The amount of mRNA expression is commonly determined by performing a reverse transcription reaction followed by either QPCR or PCR with gel electrophoresis.

Epigenetic factors, another important part of gene expression, are also crucial for informing an accurate picture of a gene. If RNA polymerase is unable to access a given gene, that gene will not be expressed. There are several epigenetic factors that contribute to a gene's expression (e.g. Histone acetylation and methylation), but the one that is easiest to test for in the laboratory is DNA methylation. To test for DNA methylation, two sets of primers and bisulfite conversion of the DNA are needed. During the bisulfite conversion reaction, unmethylated cytosines are converted into uracil [ ].