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Genetically Modified Foods Plant Genetic Engineer Prenatal Diagnosis Transgenic Organisms Ethical Issues Lasse Lindahl University of Maryland, Baltimore Ribozyme RNA David E. Loren University of Pennsylvania School of Medicine Colon Cancer Dennis N. Luck Oberlin College Biotechnology Jeanne M. Lusher Wayne State University School of Medicine Children's Hospital of Michigan Hemophilia Kamrin T. MacKnight Medlen, Carroll, LLP Patent, Trademark and Copyright Attorneys Attorney Legal Issues...

Deregulation and Cancer

Deregulation of cell cycle control proteins plays a key role in the development of cancer. Overactivation of proteins that favor cell cycle progression, namely cyclins and CDKs, and the inactivation of proteins that impede cell cycle progression, such as CKIs, can result in uncontrolled cell proliferation. In human tumors, it is genes encoding the proteins that control the transition from the G1 to the S phase that are most commonly altered. These genes include those for cyclins, CKIs, and pRb....

Antibiotic Resistance

From the human perspective, one of the significant consequences of a bacterium's ability to pass genetic information along to other cells via conjugation is its link to the widespread incidence of antibiotic resistance. The genes that encode for resistance to a variety of antibiotics like penicillin and tetracycline are commonly found on plasmids. When a population of susceptible bacteria is exposed to a given antibiotic, most of them will be killed. However, if the population contains cells...

Illustrative Examples

Blotting is perhaps best understood with illustrative examples. Suppose a student was studying a newly identified gene, X, from cows. The student then asks three basic questions as part of a research project (1) Do pigs also have gene X on their chromosomes (2) Do cows express gene X in their brain tissue (3) Is the protein product of gene X found in the cow's blood plasma Blotting experiments can answer all three of these questions. nucleotide the building block of RNA or DNA antibodies...

How the Environment Is Involved in Complex Disease

Genes are not the only things that can affect a complex trait. Often environmental factors can also be involved. The type of environmental factors can be very different for different traits. One obvious example of this is lung cancer. Smoking cigarettes greatly increases the risk of developing lung cancer. Smoking also seems to have an effect on other diseases, including some eye diseases (such as age-related macular degeneration). However, not every chronic smoker will develop lung cancer or...

Life Span and the Aging Process

How long an organism lives is called its life span. In 1998, the average life span for a human, worldwide, was sixty-six years. However, life span is a complex trait, meaning that many factors, including family history, lifestyle, disease, and residence in a developed nation, determine how long an individual's life will be. The average life span in a particular population changes as these factors change. For example, the average life span in the United States in 1900 was forty-nine in 1998 it...

Alcoholism in Humans

The techniques available for human research are more limited, and many questions remain. Although behavior geneticists now possess the techniques to identify genetic influence and to begin to identify specific genes, questions remain regarding which behaviors, actions, and activities of people are the best candidates for behavior-genetic study. Again, alcohol use and abuse provide an illustration. Alcoholism is a major social and medical problem in the United States and in most of the world. It...

Twin Studies of Alcoholism

That risk-related behaviors are evident early in life, remain stable into adolescence, and are associated with a family history of alcoholism suggests that those behaviors are, at least in part, of genetic origin. To establish that, researchers must use genetically informative study designs. One approach is to study child or adolescent twins and their parents. Several such studies, which specifically assess the initiation of alcohol use and the transition to alcohol abuse, are being conducted...

Heritability in Humans

Most family, twin, and adoption studies have shown that addiction to alcohol has significant heritability. For example, there is an increased risk for alcoholism in the relatives of alcoholics. Depending on the study, the risk of alcoholism in siblings of alcoholics is between 1.5 and 4 times the risk for the general population. The identical twins of alcoholics (who share 100 percent of their genes) are more likely to be alcoholics than the fraternal twins of alcoholics (who share only about...

Cancer Causing Chemicals

References to cancer have been found in the annals of human disease since ancient times, but the disease's association with carcinogen exposure is a relatively new concept. Sir Percival Potts, a British physician who lived in the eighteenth century, was the first to suggest that the induction of cancer might be linked to agents in the environment. Potts had observed high rates of scrotal and nasal cancer among England's chimney sweeps, men who were exposed to accumulated fireplace soot during...

Genetic Testing and Alzheimers Disease

DNA testing can be performed to determine whether an individual has a mutation in one of the causative genes and or whether he or she carries one or two copies of the APOEe4 susceptibility gene. Whether to test and which test to perform will depend on three conditions family history of dementia, age of onset of disease, and clinical status of the individual. If a person has dementia, the test result could be useful in determining that the cause of the dementia is a form of AD. If a person has...