Genetics in Medicine - Part 1
Agricultural Biotechnology - Techniques, Advantages, Concerns - Regulations
Biotechnology is the use of living organisms—microbes, plants, or animals—to provide useful new products or processes. In a broad sense, biotechnology continues a process that is thousands of years old. Using traditional plant breeding techniques, humans have altered the genetic composition of almost every crop by only planting seeds from plants with desired traits, or by controlling…
Alternative Splicing
When molecular biologists began analyzing the complete sequence of the human genome in mid-2001, one surprising observation was that humans have relatively few genes. We may have as few as 30,000 genes, only about two Introns are removed by the spliceosomes. times as many as the much simpler fruit fly, Drosophila melanogaster. How can the much greater size and complexity of humans be encoded…
Alzheimer's Disease - First Description Of Ad, An Evolving Understanding Of Dementia, Genetics Of Alzheimer's Disease
Alzheimer's disease (AD) is a diagnosis applied to a group of degenerative brain disorders with similar clinical and pathological characteristics. It is the most common cause of dementia, with onset of symptoms after the age of fifty-five years. It is recognized as a major public health concern in societies with an aging population. AD affects four million people in the United States. At le…
Ames Test
O6-ethylguanine. The Ames test is a protocol for identifying mutagenic chemical and physical agents. Mutagens generate changes in DNA. Many mutagenic agents modify the chemical structure of adenine, thymine, guanine, and cytosine, the bases in DNA, changing their base-pairing properties and causing mutations to accumulate during DNA synthesis. Ethyl methanesulfonate (EMS), for example, is a…
Androgen Insensitivity Syndrome - Sexual Development, Testosterone And Its Receptor, The Consequences Of Androgen Insensitivity, The Androgen Receptor Gene And Protein
Androgen insensitivity syndrome (AIS) is a disorder caused by mutation of the gene for the androgen receptor. This protein binds testosterone and regulates the expression of other genes that stimulate male sexual development. Testosterone is the principal male androgen. AIS is an X-linked recessive disorder that completely or partially prevents development of male sexual characteristics despite th…
Antibiotic Resistance - Mechanisms Of Resistance, Resistance And Public Health
Antibiotic resistance is the ability of a bacterium or other microorganism to survive and reproduce in the presence of antibiotic doses that were previously thought effective against them. Examples of microbe resistance to antibiotics dot the countryside, plaguing humankind. For instance, in February 1994 dozens of students at La Quinta High School in southern California were exposed to the pathog…
Apoptosis - Why Cells Commit Suicide, The Regulatory Mechanism
Death is an inevitable fact of life for organisms. Increasingly, biologists have come to realize that death is also, in many cases, an important and predestined fate of individual cells of organisms. Apoptosis is a process by which cells in a multicellular organism commit suicide. While cells can die as a result of necrosis, apoptosis is a form of death that the cell itself initiates, regulates, a…
Arabidopsis thaliana - A Small And Simple Genome, Arabidopsis And Transformation, The First Completely Sequenced Plant Genome
Arabidopsis thaliana, or thale cress, is a small flowering plant in the mustard family. Arabidopsis has no inherent agricultural value and is even considered a weed, but it is one of the favored model organisms of plant geneticists and molecular biologists, and it is the most thoroughly studied plant species at the molecular level. Model organisms have traits that make them attractive and convenie…
Attorney
Attorneys involved with genetics include criminal prosecutors (district attorneys), public defenders, environmental lawyers, family lawyers, and patent attorneys. Genetics is relevant in the areas of identification of suspects and victims, identification of illegal goods (for example, items that involve the killing of endangered animals), environmental monitoring for harmful microorganisms, parent…
Automated Sequencer - The Need For Automated Sequencing, Refinements In Automation
The process of determining the order of nucleotides (A, C, G, and T) along a DNA strand is called DNA sequencing. Knowing the nucleotide sequence of a gene or region of DNA is important in studying relatedness between species and between individuals and for a better understanding of how genes function. Several techniques have been developed for "reading" the sequence of any particula…
Balanced Polymorphism
Balanced polymorphism is a situation in which two different versions of a gene are maintained in a population of organisms because individuals carrying both versions are better able to survive than those who have two copies of either version alone. The evolutionary process that maintains the two versions over time is called balancing selection. Genes are carried on chromosomes. Different versions …
Behavior - Twin And Adoption Studies, Complex Genetics, Animal Models, Alcoholism In Humans, Twin Studies Of Alcoholism
What is behavior? A dictionary definition reveals that behavior consists of our activities and actions, especially actions toward one another. As such definitions suggest, many behavioral terms have meaning only in social comparisons: We identify others as contentious, courteous, or conscientious only by their actions in social contexts. A long-standing question in science and in everyday affairs …
Bioinformatics - Databases And Analysis Programs, Applications Of Bioinformatics To Drug Discovery - Specialists
Bioinformatics is the use of mathematical, statistical and computer methods to analyze biological, biochemical, and biophysical data. Because bioinformatics is a young, rapidly evolving field, however, it also has a number of other credible definitions. It can also be defined as the science and technology of learning, managing, and processing biological information. Bioinformatics is often focused…
Biopesticides - Living Organisms Serving As Biopesticides, Genetically Modified Organisms As Biopesticide Producers, Disease Resistance In Crops - Natural Chemical Defenses, Herbicide-Resistant Crops
Plants, growing in the wild or in cultivation, face numerous threats from insects, bacteria, viruses, and fungi, as well as from other plants. Biopesticides are inert substances or living organisms that can help protect plants from such threats. Chemical pesticides can offer similar protection but, by contrast, are neither alive nor made by living organisms. A variety of chemicals produced by plan…
Biotechnology Entrepreneur
The biotechnology entrepreneur often starts with a technical background, most commonly including scientific laboratory research. It is quite common for scientists who have spent a number of years in an academic environment to start a new company based on a technology platform or a novel discovery they made during their tenure at a university or research institute. Alternatively, a scientist or a g…
Biotechnology: Ethical Issues - Agriculture, Health Care, New Challenges
Biotechnology is the use of organisms or their parts or products to provide a valuable substance or process. Fermentation using microorganisms in brewing, baking, and cheese production are biotechnologies that date back centuries. Production of human insulin in bacteria to treat type I diabetes mellitus without causing allergic reactions is a more modern example of biotechnology. Two widely used b…
Birth Defects - Various Causes, Various Treatments, Single-gene Mutations, Autosomal Dominant Disorders, Functional Birth Defects
A birth defect is an anomaly that is congenital, or present from birth. Birth defects are the leading cause of infant mortality, causing 22 percent of all infant deaths. Approximately 3 to 4 percent of all live births are affected by a birth defect; the causes of most of them are unknown. Some birth defects are considered to be physical, while others are thought of as functional. Physical birth de…
Blotting - The Procedure, Illustrative Examples
Blotting is a common laboratory procedure in which biological molecules in a gel matrix are transferred onto nitrocellulose paper for further scientific analysis. The biological molecules transferred in this process are DNA fragments, RNA fragments, or proteins. Because the isolation and characterization of these types of materials is at the center of much molecular biology research, blotting is o…
Breast Cancer
Breast cancer remains the most common cause of cancer among women in the United States, and it results in more deaths from cancer among women than any other type of cancer, except lung cancer. Over 40,000 women die from breast cancer in the United States each year. A long history of research, now coupled with the new information emerging from the field of molecular genetics, is beginning to explai…
Cancer - A Genetic Disease, Classification Of Cancer Types, Benign Or Malignant Tumor, Type Of Cell - Type of Tissue, Site of Origin
Cancer is a number of related diseases that are characterized by the uncontrolled proliferation and disorganized growth of cells. Tumor cells invade and destroy normal tissues and may spread throughout the body via the circulatory systems. The body consists of many different organs, which in turn are composed of several different types of tissues. There are three major categories of tissue-related…
Cardiovascular Disease - Finding Genes For Cardiovascular Disease, Ongoing Studies, Goals Of Genetic Studies
Cardiovascular disease is a set of diseases affecting the heart and blood vessels. As with most chronic diseases whose incidence increases with age, it involves both inherited and environmental contributors and is therefore classified as a complex genetic disease. Most researchers believe that all major risk factors for cardiovascular disease have been identified. It is estimated that cigarette sm…
Cell Cycle - Control Of The Cycle, Proteins That Regulate The Cycle, Deregulation And Cancer
The cell cycle is the process by which a cell grows, duplicates its DNA, and divides into identical daughter cells. Cell cycle duration varies according to cell type and organism. In mammals, cell division occurs over a period of approximately twenty-four hours. In multicellular organisms, only a subset of cells go through the cycle continuously. Those cells include the stem cells of the hematopoi…
Centromere
During mitosis in a typical plant or animal cell, each chromosome divides longitudinally into two sister chromosomes that eventually separate and travel to opposite poles of the mitotic spindle. At the beginning of mitosis, when the sister chromosomes have split but are still paired, every chromosome attaches to the spindle at a specific point along its length. That point is referred to as the cen…
Chromosomal Aberrations - Advances In Chromosomal Analysis, Chromosomal Aberrations, Aneuploidy, Disorders Associated With Aneuploidy, Abnormalities Of Chromosomal Structure - Unbalanced Chromosome Rearrangements
Chromosomal aberrations are abnormalities in the structure or number of chromosomes and are often responsible for genetic disorders. For more than a century, scientists have been fascinated by the study of human chromosomes. It was not until 1956, however, that it was determined that the actual diploid number of chromosomes in a human cell was forty-six (22 pairs of autosomes and two sex chromosom…
Prokaryotic Chromosome
The bacterial or prokaryotic chromosome differs in many ways from that of the eukaryote. The term "eukaryote" comes from the Greek and means "true nucleus." Eukaryotic cells have a double membrane (the nuclear membrane) surrounding the nucleus, the organelle that contains several chromosomes. In contrast, the term "prokaryote" means "primitive nucle…
Classical Hybrid Genetics
Common garden peas (Pisum sativum) are wonderful when eaten raw. Gregor Mendel (1822-1884) no doubt ate his share. Today he is recognized for using peas to establish the science of genetics. Mendel investigated hereditary patterns of hybrids. Hybrids are off-spring from two organisms that are of different breeds, varieties, or species. Hybrids create new cultivars, from new apple varieties to tang…
Clinical Geneticist
Medical genetics is the application of genetics to the study of human health and diseases. As a profession, medical genetics is usually a mixture of both clinical services and research. Worldwide, services can include diagnosis, counseling, and management of birth defects and genetic disorders. How medical genetics is actually practiced depends on several factors, including the expertise and train…
College Professor
Professors of genetics at colleges and universities teach, perform research, and handle administrative responsibilities. Professors may teach at the undergraduate or graduate levels, or both. Undergraduate teaching involves class lectures, small group seminars, and hands-on laboratory sessions. Professors evaluate students based on their performances on examinations, essays, and laboratory work, a…
Colon Cancer - Developing Cancer, Major Genes Involved, Familial Adenomatous Polyposis (fap), Hereditary Nonpolyposis Colon Cancer - Other Risk Factors
Colon cancer is the second leading cause of cancer death in the United States, occurring in approximately 5 percent of the population and resulting in roughly 55,000 deaths annually. New cases of colorectal cancer are diagnosed in approximately 90 per 100,000 people annually. The majority of cases occur in individuals older than age fifty. Of those who suffer from colorectal malignancy, an estimat…
Color Vision
Sight is a complex process that results when visible light, a narrow band of the electromagnetic spectrum between 400 and 700 nanometers (nm), is converted into signals that can be interpreted by the brain. This process involves special light-sensitive cells called photoreceptors that are located in the retina, a thin structure that lines the inside of the eye. These cells capture packets of light…
Complex Traits - How Genes Are Involved In Complex Disease, How The Environment Is Involved In Complex Disease, Genes And Environmental Factors May Interact
Complex traits are those that are influenced by more than one factor. The factors can be genetic or environmental. This is in contrast to simple genetic traits, whose variations are controlled by variations in single genes. Examples of simple traits include Huntington's disease and cystic fibrosis. Each of these traits is caused by a mutation in a single gene that alters or destroys the fun…
Computational Biologist
A computational biologist is a scientist who develops and utilizes computational tools to analyze biological data. The Human Genome Project and other large sequencing projects have generated an extraordinary amount of data. Biologists are now faced with the challenge of extracting meaning from linear sequences composed of billions of base pairs. The work of computational biologists is indispensabl…
Conservation Biology: Genetic Approaches - Categories Of Threatened Populations, Conservation Genetics Applications, The Tools Of Conservation Genetics, Implication Of Genetics For Conservation In The Wild
Conservation biology is a multidisciplinary field dedicated to protecting global biodiversity and critical habitats. It incorporates biological approaches such as ecology, evolution, and behavior studies, as well as other disciplines, such as political science, law, economics, and cultural anthropology. One of the major goals of conservation biology is preserving critical habitats and the species …
Max Delbrück
Physicist, Molecular Biologist 1906-1981 Max Delbrück made major contributions to the understanding of replication and viral function. Raised in Berlin in a distinguished family of German intellectuals, Delbrück trained as a physicist with Niels Bohr and other leaders in the field of quantum mechanics. In the early 1930s his interests turned toward biology and the nature of the gene. Thi…
Genetic Control of Development - The Importance Of Transcription Factors, The European Way And The American Way, Morphogens And Gradients
Development is the process through which a multicellular organism arises from a single cell. During development, cells become specialized, or differentiated, taking on different functions and forms. The organism develops a characteristic three-dimensional shape, the parts of which (such as limbs and organs) continue to maintain the same relationship to each other even as the organism grows. How th…
Diabetes - Type 1 Diabetes, Type 2 Diabetes, Other Specific Types Of Diabetes, Genetic Susceptibility To Complications - Gestational Diabetes Mellitus
Diabetes mellitus is a group of diseases characterized by elevated levels of glucose in the blood. Diabetes is caused by problems producing or responding to the hormone insulin. Insulin is produced in the pancreas by specialized cells called beta cells, in response to the presence of glucose absorbed through the gastrointestinal tract following a meal. Insulin promotes the uptake of glucose into m…
DNA - The Components of DNA, The Structure of Double-Stranded DNA, Alternative DNA Conformations
DNA (deoxyribonucleic acid) was discovered in the late 1800s, but its role as the material of heredity was not elucidated for fifty years after that. It occupies a central and critical role in the cell as the genetic information in which all the information required to duplicate and maintain the organism. All information necessary to maintain and propagate life is contained within a linear array o…
DNA Polymerases - The Dna Polymerase Mechanism, The Variety Of Dna Polymerases
DNA polymerases are proteins that synthesize new DNA strands using preexisting DNA strands as templates. Before one cell divides to produce two cells, the DNA containing the genetic information in it must be duplicated for the new cell, in a process known as polymerization. In human cells, duplicating the DNA genome requires the polymerization of 2.91 billion nucleotides, the building blocks of DN…
DNA Repair - Sources Of Damage, Base Excision Repair, Nucleotide Excision Repair, Dna Mismatch Repair, Future Directions - Types of DNA Damage
When it was discovered that DNA is the macromolecular carrier of essentially all genetic information, it was assumed that DNA is extremely stable. Consequently, it came as something of a surprise to learn that DNA is actually unstable and subject to continual damage. When DNA damage is severe, the cell is unable to replicate and may die. Repair of DNA must be regarded as essential for the preserva…