...A mutation is a change in DNA, which is the instructions for how to create the organism, and the mutation is when the DNA differs from what it was supposed to be when it replicated itself. The letters A, T, G, and C represent the bases adenine, thymine, guanine, and cytosine; in addition, the order the bases are in make up the instructions of the genetic code. The instructions of DNA are matched with amino acids the cells use to create proteins. The molecular basis of DNA mutations is a change in the DNA’s bases, happening either spontaneously or being caused by mutagens, which can lead to effects that help, harm, or have no effect the organism. DNA mutations happen either naturally or are caused by mutagens, which are something in the environment...
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...insecticide resistance: some insects carry trait of resistance in their genes * Processes in Microevolution -Mutation -Non-random mating -Genetic Drift -Natural Selection -Gene Flow * Hardy-Weinburg Theorem: Frequencies of alleles and genotypes are preserved from generation to generation in populations that are not evolving -p2 + 2pq + q2 = 1 * Hardy-Weinburg tells us that we will never get rid of bad genes and it’s used to figure how gene populations change over time * The Hardy-Weinberg theorem describes a pop’n that is not evolving. It has 5 assumptions: 1. Genetic Drift: This represents random changes in small gene pools due to sampling errors in propagation of alleles. The bottleneck effect and founder effect are prime examples of genetic drift. In either case the number of individuals in a population is drastically reduced distorting the original allelic frequencies. (H-W assumes large population) 2. Gene Flow: The movement of alleles into and out of a gene pool. Migration of an organism into different areas can cause the allelic frequencies of that population to increase. Most populations are not isolated, which is contrary to the Hardy-Weinberg Theorem. (H-W assumes the population isolated from others) 3. Mutations: These changes in the genome of an organism are an important source of natural selection.(H-W assumes no net mutation) 4. Nonrandom mating: Inbreeding is a popular form of nonrandom mating. Individuals will mate more frequently...
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...SSM2 Introduction Eukaryotic cells contain hair-like projecting organelles, known as cilia and flagella, which are involved in many sensory and motile functions of the human body, thus any abnormalities in their characteristic 9+2 axonemal structure or their functioning can lead to many different disease processes. In my review I will look at the structure and functions of eukaryotic cilia in the human body and the ways in which mutated or abnormal gene expression can result in their malfunction and cause disease, looking specifically at Primary Ciliary Dyskinesia and the DNAH5 gene. Structure of cilia Cilia and flagella have very similar structures. Cilia are about 0.25 micrometers in diameter and 2-20 micrometers long (4) and flagella tend to be longer, 10-100micrometers and fewer per cell than cilia. They are both synthesized by and project from structures known as basal bodies which are a type of centriole located at the cells periphery, which anchors cilia to the cells body and cytoskeleton. They are also microtubule organizing centers which control the direction of the movement of the cilia (1). Both cilia and Flagella are made up of nine outer fused pairs of microtubule doublets (see figure 1) (3)(8), one of which is complete (A- tubule) and one incomplete (B-tubule), which join together via nexin protein links creating a circular network of microtubule doublets(3) (see figure 1) which surrounds two central single microtubules...
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...Table 1 shows the different disorders that may overlap with Marfan Syndrome because of their clinical features. It is therefore important that all these clinical manifestations are ruled out before diagnosing an individual of a potential disorder. A disorder that overlaps mostly with the many features of the Marfan syndrome is Loeys-Dietz syndrome (LDS) as a result of mutations in TGFBR2, TGFBR1, SMAD3 and TGFB2.4 Patients with LDS present with malar hypoplasia, arched palate, scoliosis, dural ectasia, aortia aneurysms and dissections.2 Although they have long finger, bone overgrowth is often absent and does not show ectopia lentis.2 Distinctive features include high frequency hypertelorism learning disability, congenital heart disease and...
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...Rachelle Jelosek Idaho State University Jackson is a healthy twenty-seven year old male who recently presented to his doctors office inquiring about genetic testing. Jackson recently married, and his wife Alisha is anxious to start a family. Unfortunately Jackson does not share Alisha's enthusiasm because he fears that he is a carrier of a deadly genetic mutation. Just five years ago Jackson's mother was diagnosed with Huntington's Disease at the age of 43 and Jackson's grandmother succumbed to the disease at the age of 68. Jackson is an only child and although unconfirmed and heavily denied by his family Jackson is convinced that his mother discovered her ill fate shortly after he was born. Jackson's wife and father do not want him to be tested for the disorder because they fear a positive diagnosis will destroy any life he has now and in the future . Jackson has endured years of watching his loved ones suffer and does not want to pass the disorder on to his children. The purpose of this paper is to define and describe Huntington's disease (HD), explain inheritance patterns, describe the specific gene mutation seen in patients with HD, discuss reproductive issue and outline the ethical and social implications associated with genetic testing. Huntington's disease was named after Dr. George Huntington, who is credited for discovering the hereditary disorder in 1872(Huntington’s Disease Society of America, 2008). HD progressively destroys neurons in the basal ganglia...
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...Rett Syndrome Joseph Lee 4th Period Rett Syndrome is a disorder which affects the nervous system and is found almost exclusively in girls. One in 10,000-20,000 newborn babies are born with Rett Syndrome, making this disorder very rare. Rett Syndrome is often described as autism, cerebral palsy, Parkinson’s, epilepsy, and various anxiety disorders wrapped into one. In this paper, I will discuss what exactly Rett Syndrome is, who discovered it, how he discovered it, what its causes are, what the symptoms are, the disorder’s course, and possible treatments for the disorder. Said Dr. Rett at a conference regarding the disorder which bears his name: These three words summarize best our task: To live, to love, and to learn. We are aware of the fact that many mysteries of this syndrome still remain undisclosed, and therefore, for the time being, we have no option but to live with it. However, the children with their very special ways give us enough impulse to share their lives. It is a further mystery of this syndrome that the affected children render it easy for us to love them. A dominating factor in the care of such children is that they understand us and we understand them. Their appearance and the sparkle in their eyes make it easy to love them. Daily care for them and working with them gives us grownups strength, enabling us to learn the special treatment required, thus furthering our own development. To...
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...Genetic testing is a scientific process in which an individual’s DNA can be screened for mutations or variations that may cause certain diseases or dysfunctions. It is my opinion that standard genetic testing for disease or the predisposition to disease is purely beneficial. Having clear answers as to whether or not a person may carry a higher risk for some diseases may in fact save their life, or the lives of their current or future children. However, over the years of development of the science, more and more controversial types of testing have developed. In this paper, the science of genetic testing will be introduced by going through a brief history, the different types of genetic testing available, as well as the controversies that surround them. History Genetic testing had a very positive and productive start. The first usage of Genetic Testing occurred over half a century ago, beginning with the testing of infants for PKU, or Phenylketonuria, “an inborn error of metabolism in which an amino acid buildup in the blood causes mental retardation.” (Lewis) To test infants, a drop of blood was taken from their heel while at the hospital after birth. If a child was found positive for PKU, dietary treatment was used to prevent loss of brain function. Testing was reliable and results were accurate. The disease being tested for was easily treatable, and every child that came through was tested without a problem. (Lewis) In the 1970’s, doctors began the process of testing...
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...PGD goes against the science of genetics, basically choosing disorders that should not be inherited, making PGD a socio scientific issue. These people may not know they are carriers of a disorder until they have an affected child, there is a 50%-50% chance of the embryo inheriting the disorder if the parents are affected and carrying the trait for the disorder. The PGD process begins occurring with the ovarian stimulation and IVF. The second part of this procedure is the blastomere biopsy on day 3. Leading to the genetic analysis of the embryo for an inherited disorder. This is done by genetic screening and genetic testing the embryo/baby. “Genetic testing usually involves testing an individual for the genetic change (mutation) underlying a condition or abnormality that may be suggested by other evidence ”. “Genetic screening may involve testing members of a population (or sub-population) for a defect or condition, usually where there is no prior evidence of its presence in individuals or their relatives, and as part of a public health service. Alternatively, the offer of screening may be limited to a sub-population that is at particular risk of a genetic condition ”. The third step in completing the PGD procedure is the transfer of the unaffected embryo into back into the woman. The final part of the PGD procedure being the...
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...Evolvability of Animal Developmental Systems: Remarks on their Modularity and Robustness Riddhi Benani Department of Life Sciences Imperial College London, UK Supervisor: Prof Armand Leroi June 11, 2012 Abstract The ultimate aim of Evolutionary developmental biology (Evo-Devo) is to answer questions about evolvability of animal developmental systems. Evolvability or the ability to evolve is a ubiquitous property of living organisms. More specifically, it is the capacity to generate heritable, non-lethal phenotypic variation. Biologists have long recognized that evolvability of developmental programs in animals is key to their complex morphological architecture. However there is an increasing need to synthesize known facts about the developmental phenomena into mechanistic descriptions of complex systems. This ambition demands the need to understand the underlying determinants of evolvable developmental systems. I aim to review the dynamics of two systems-level phenomena: modularity and robustness and their evolutionary implications. Despite a plethora of literature, these terms have remained very ambiguous. Modularity reduces interdependence of components and confers robustness. Robustness, which is broadly understood, as the insensitivity of a biological systems functionalities to perturbations is another design principle in itself. Such robustness could enhance the potential for future evolutionary innovations. Both these properties therefore affect evolvability of a lineage...
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...Student Examination into the Causes, Treatment, and Prognosis of Osteogenesis Imperfecta Anitra Swann Baltimore City Community College Professor McNair AH 130 October 18, 2011 Abstract Osteogenesis Imperfecta is a heritable disorder of bone formation resulting in low bone mass and a propensity to fracture. It exhibits a broad range of clinical severity, ranging from multiple fracturing in utero and perinatal deaths to normal adult stature and a low fracture incidence. The disorder is currently classified into seven types based on differences in bone architecture. In addition to its primary effect on the skeletal system, the alterations in connective tissue may affect several extra skeletal structures, such as the cardiovascular system, sclera, middle and inner ear, tendons/ligaments, and central nervous system. Patients with Osteogenesis Imperfecta also have a greater incidence of airway anomalies, cardiovascular anomalies, and increased incidence of perioperative bleeding, easily fractured bones and teeth. Treatment of Osteogenesis Imperfecta by bisphosphonate therapy can improve bone mass in all types of the disorder, and while not being a cure for the disorder does improve the quality of life of the patient. This paper will examine the causes, treatment, and prognosis of Osteogenesis Imperfecta. Student Examination into the Causes, Treatment, and Prognosis of Osteogenesis Imperfecta Osteogenesis Imperfecta (OI) is an abnormally brittle bone disease that is inherited...
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...metastasis 2) Adenoma-Carcinoma sequence a. Majority of colon cancer arise from polyps (adenomas) b. Accumulation of genetic mutations / events resulting in uncontrolled growth (dysplasia) c. Over time results in carcinoma 1. APC mutation on chromosome 5 (Early adenoma) 2. K-ras mutation on chromosome 12 3. TGF β, SMAD4 mutation (Late adenoma) 4. P53 mutation on chromosome 17 (Carcinoma) 5. Metastasis d. Evidences 1. Foci of cancer are frequently seen within large polyps 2. Adenomatous (dysplastic) tissue is frequently seen adjacent to large cancers 3. Similar distribution of polyps and cancers within the colon 4. 10-15 year progression of polyp to cancer 5. Reduction of polyps causes reduction in subsequent incidence of cancer 3) Tumorgenesis a. Chromosomal instability 1. Gain of function – oncogenes 2. Loss of function – tumor suppressor genes (APC genes in FAP) b. Epigenetic alteration (microsatellite instability) i. Altered methylation or defective mismatch repair genes resulting in erroneous DNA synthesis Increased mutation rate and microsatellite instability ii. Exemplified by germline mutations causing HNPCC /Lynch syndrome which is characterized by premature and proximal location of colon cancer c. Common pathways 1. Mutations in Ras pathway, Wnt pathway, loss of p53 tumor suppressor, and SMAD2/4 mutations i. Decreased exit or increased entry into cell cycle, and anti-apoptotic signaling Increased cell growth, decreased cell...
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...DNA DNA or Deoxyribonucleic acid is the very building block needed in the creation of life. It is composed of genetic instruction to map out the creation of an entire organism. DNA is well suited in the storage of biological information. Yet with all of this complex information there are certain chemicals or forms of energy that can damage or alter this special coding. In process of damaging or altering the coding of DNA the most dreaded situation of a cancerous cell can be formed. To start let’s look at the different kinds of radiation that may or may not effect DNA. Alpha, Beta, and Gamma Radiation Ionizing Radiation can change the way our body’s work and develop. Direct includes covalent linkage between nitrogenous bases, and creating structure like thymine dimmers. Indirect is when it interacts with water to create free radicals which can interact with a person’s DNA. It can cause single or double stranded breaks in the sugar- phosphate backbone. (Buttons, n.d.) Alpha Radiation is a process that needs to be swallowed, inhaled, and or absorbed into the blood stream. This can increase the risk of cancer also known as lung cancer. Radon is a silent but deadly killer. To determine if one has been affected by alpha particles testing would be completed with special equipment and gear to prevent those from any exposure. Beta Particles can be a helpful process of treatment to many, such as treating thyroid disorders, cancer, and Graves’ disease (hyperthyroidism). It also...
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...earth is teeming with living things. We can easily see some of the larger organisms—trees, grass, flowers, weeds, cats, fish, squirrels, dogs, insects, spiders, snails, mushrooms, lichens. Other organisms are everywhere, in the air, in water, soil and on our skin, but are too small to see with the naked eye—bacteria, viruses, protists (single celled eukaryotes such as amoebae), and tiny plants and animals. Life is remarkable in its complexity and diversity, and yet it all boils down to a very simple idea—the instructions for making all this life are written in nucleic acids, usually DNA. Most organisms have a set of DNA that contains the instructions for making that creature. This DNA contains four “letters” in which these instructions are written—A, T, G, and C. The only difference between the code for a dog and the code for a geranium is in the order of those letters in the code. If you took the DNA from a human and rearranged the letters in the right way, you could produce an oak tree—arrange them slightly differently and you would have a bumble bee—arrange them again and you would have the instructions for making a bacterium. Acting through more than two billion years, the process of evolution has taken one basic idea—a molecular code that uses four letters—and used it over and over, in millions of combinations to produce a dazzling array of life forms. As far as we know, we are the only creatures on the planet that have figured this out. The members of our species who get...
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...after receipt of your corrected proofs. Jaworek et al. Orphanet Journal of Rare Diseases 2012, 7:44 http://www.ojrd.com/content/7/1/44 1 2 3 4 5 6 7 RESEARCH Open Access Molecular genetic studies and delineation of the oculocutaneous albinism phenotype in the Pakistani population Thomas J Jaworek1, Tasleem Kausar2, Shannon M Bell1, Nabeela Tariq2, Muhammad Imran Maqsood2, Asma Sohail2, Muhmmmad Ali2, Furhan Iqbal2, Shafqat Rasool3, Saima Riazuddin1,4,5,6, Rehan S Shaikh2,8* and Zubair M Ahmed1,2,4,5,6,7* 8 Abstract 9 Background: Oculocutaneous albinism (OCA) is caused by a group of genetically heterogeneous inherited defects that result in the loss of pigmentation in the eyes, skin and hair. Mutations in the TYR,...
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...What are genetic mutations? A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. Mutations can occur in two different types of cells: 1. Somatic (body) cells – occurs to the DNA that controls regulation of the cell cycle. * Somatic mutations do not affect the individual. * can not be passed on to the next generation 2. Gamete (sex) cells- means that every cell of the developing fetus/baby will have that mutation. * Gamete mutations usually do affect the individual with some genetic disorder. * •Gamete mutations can be passed on to the next generation. There are two types of mutations that can occur in gamete cells: 1. Gene Mutations * . Point Mutation: a single point in the DNA sequence is affected. “The protein may be slightly affected or not affected at all. “ * • Can be a substitution in which one base is changed into another base 2. Chromosomal Mutations- has five different types 1. Deletion : Involves the loss of all or part of a chromosome 2. Duplication: Involves the production of extra copies of parts of the chromosome 3. Inversion : Reverses the direction of parts of a chromosome. 4. Translocation : When one part of a chromosome breaks off and attaches...
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