...Thomas Morgan Hunt, was the first to discover the Drosophila as a model organism to study genetic hereditary. His research showed that the species could randomly obtain genetic mutations that could be visible in the parental generation. Since fruit flies have a diploid chromosome number of 8 (haploid 4), chromosomal types are easily identified. Various genetic crosses are able to determine that the x-linked gene is found on chromosome 1, while the autosomal genes are located on the 2-4 chromosomes. Mapping of unknown mutations by reciprocal crosses can identify if the alleles are x-linked or autosomal and if these alleles are dominant or recessive. Once the type of allele is determined, other genetic crosses can determine the location of the chromosome that the mutagen is one. For the x-linked mutations, a three factor test cross can induce map order and distance. The physical distance separating two genes on the chromosome (map distance) is directly related the frequency of recombination between markers during meiosis. The greater the map distance of the genes, the greater the probability that there is crossing over when the chromosomes segregate in meiosis. In this virtual experiment, six mutations (crossveinless, dumpy, ebony, eyeless, sable, & singed) were analyzed with Drosophila. Reciprocal crosses will be performed to decipher the mutant allele. Aside from x-linked mutagens which reside on chromosome 1, other crosses will be executed to discover the chromosomal...
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...• Curly x Wildtype “+” the wildtype (normal gene) and “Cy” the curly (mutant gene) 1. Given that Curly is a dominant trait, what percentage of these offspring should be expected to express the mutation (have curly wings)? B. 50% of the offspring are expected to have the curly wing mutation. 2. What percentage will have the normal (wildtype) wings? C. 50% of the offspring will have normal wildtype wings. 3. Organisms are called carriers of a gene if they do not express it themselves but they can pass it on to their offspring. Is it possible for a fly to be a carrier of the Curly gene? B. No • Ebony x Wildtype “+” the wildtype (normal gene) and “e” the ebony (mutant gene) 1. Given that ebony is a recessive trait, what percentage of these...
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...multiple allele n. Any of a set of three or more alleles, or alternative states of a gene, only two of which can be present in a diploid organism. Allele Jump to: navigation, search An allele (UK /ˈæliːl/ or US /əˈliːl/), or allel, is one of a number of alternative forms of the same gene or same genetic locus (generally a group of genes).[1][2] It is the alternative form of a gene for a character producing different effects. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation. However, many variations at the genetic level result in little or no observable variation. Most multicellular organisms have two sets of chromosomes, that is, they are diploid. These chromosomes are referred to as homologous chromosomes. Diploid organisms have one copy of each gene (and therefore one allele) on each chromosome. If both alleles are the same, they are homozygotes. If the alleles are different, they are heterozygotes. A population or species of organisms typically includes multiple alleles at each locus among various individuals. Allelic variation at a locus is measurable as the number of alleles (polymorphism) present, or the proportion of heterozygotes in the population. For example, at the gene locus for the ABO blood type carbohydrate antigens in humans,[3] classical genetics recognizes three alleles, IA, IB, and IO, that determine compatibility of blood transfusions. Any individual has one of six possible genotypes (AA, AO...
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...Chapter 14 Mendel and the Gene Idea Lecture Outline Overview • Every day we observe heritable variations (such as brown, green, or blue eyes) among individuals in a population. • These traits are transmitted from parents to offspring. • One possible explanation for heredity is a “blending” hypothesis. ° This hypothesis proposes that genetic material contributed by each parent mixes in a manner analogous to the way blue and yellow paints blend to make green. ° With blending inheritance, a freely mating population will eventually give rise to a uniform population of individuals. ° Everyday observations and the results of breeding experiments tell us that heritable traits do not blend to become uniform. • An alternative model, “particulate” inheritance, proposes that parents pass on discrete heritable units, genes, that retain their separate identities in offspring. ° Genes can be sorted and passed on, generation after generation, in undiluted form. • Modern genetics began in an abbey garden, where a monk named Gregor Mendel documented a particulate mechanism of inheritance. A. Gregor Mendel’s Discoveries 1. Mendel brought an experimental and quantitative approach to genetics. • Mendel discovered the basic principles of heredity by breeding garden peas in carefully planned experiments. • Mendel grew up on a small farm in what is today the Czech Republic. • In 1843, Mendel entered an Augustinian monastery. • He...
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...Unit Three Aha thesis - Genetics Genetics are what make up who you are. Scientists for centuries have been studying genetics on how they pass traits, how their structure matches their function, and generally how they work. How Living Organisms pass Traits Genetics are how the next generation of a species is formed. There are two different ways a new generation is formed and traits are passed, asexual and sexual reproduction. With sexual reproduction is requires two partners and leads to genetic diversity. Asexual and sexual reproduction are both very different strategies of reproduction. Sexual reproduction requires two parents, and gives the child a unique combination of genes from both parents. Sexual reproduction is typically used by more complex organisms, leading to the parents most likely raising their offspring. Asexual reproduction requires only one parent, and the offspring is an exact copy of the parent through a process called mitosis (ISN pg. 93). Mitosis is a part of the cell cycle division process that occurs when...
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...determining the physical makeup of a child, the psychological or mental makeup of a child and also certain abnormalities such as Tay-Sachs disease. The role of genetics can predetermine many different characteristics of a human being. Genetics play a role in development of physical traits. Genes are passed down from the mother and the father but before we can get there, let’s start at the beginning. A sperm and an egg each have one copy of the gene to make up an individual. When the sperm fertilizes the egg, two copies of each gene are present and the new life begins. Each egg and sperm cells contain 23 chromosomes. When they are joined together a fertilized egg will be formed with 46 chromosomes but sometime the egg or sperm will not divide correctly. Sometimes when the egg and sperm unite they will have too many or two few chromosomes. When the cell has the wrong number of chromosomes this can result in a chromosomal abnormality (Birth Defects, n.d.). Children can inherit physical traits from either parent. Genes are segments of DNA that are carried on the chromosomes and determine specific characteristics such as height, eye or hair color. There are different types of genes, recessive...
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...only have this disease if both parents are carriers and they receive two recessive alleles. There are five effects of the disease at different levels. At the DNA level the mutation causes the sequence to be coded GTG, CAC instead of GAG, CTC which results in a mutant protein. At the protein level the hemoglobin clump together which makes it hard for it to travel through arteries and vessels. At the cellular level the blood cell because “sickle shaped” due to the lack of oxygen that constricts blood flow. In an organism sickle cell anemia causes pain and fatigue during exercise. The only positive effect is the resistance to malaria. These examples show how a small mutation has a very large (sometimes fatal) effect. Therefor large and small mutations can have big effects (“A case study of the effects of mutation: Sickle cell anemia,” 2015) 1. Sickle Cell Anemia is an autosomal recessive disease. These means that both parents of the offspring have to have one normal gene and one mutated gene. The mutated gene is caused by substitution in an amino acid that distinguishes if a person is normal or has the disease. During meiosis chromosomes cross over which results in many possible DNA combinations. Simply by the luck of the genetic hand the two recessive chromosomes may come together and the offspring has Sickle Cell Anemia. A person can only have this disease if and only if they have both recessive genes ( “Sickle Cell Disease,”...
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...Class Final: The genetics of cancer * Cancer is when mitosis goes wrong! * Cancer cells lack regulated ability to divide only when needed so they divide uncontrollably. * Hyperplasia- Beginning of cancer development; heightened cell division that can create tumor (neoplasm) * Dysplasia- The change in cells/tissue * Cancer cells go from being complex to primitive—which means cancer cells lose their shape, size and ability to function like normal cells * Cancer originates due to mutations within the DNA, in sequence of nucleotides of genes * Malignant tumors and neoplasms are referred to as cancer; benign neoplasms are NOT cancer * In situ tumors- Precurser to cancer/ precancerous * Very dangerous tumor cells (what’s detected in screenings) Causes of cancer: 1. If there’s mutation in the Proto-oncogenes (tumor suppressor genes), which code for proteins and regulates mitosis… then there will definitely be problem with normal cell division. 2. Carcinogens are substances or physical agents that lead to development of cancer when body is exposed to them. 3. General mutations due to internal/external factors can cause cancer. a. Internal factors- errors in DNA replication; Free radicals; errors in protein synthesis b. External factors- Infectious agents (bacteria/viruses); pollution and chemicals in environment; Radiation (sun); medical treatment (chemo); Lifestyle factors (diet, tobacco) Benign vs. Malignant ...
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...though the Y chromosome determines if the offspring will be male, the X chromosome has genes that control certain human characters; these genes are called sex-linked genes because they are linked to a certain sex. There are approximately 1,098 sex-linked genes that code unusual inheritance patterns other than the female sex trait. Some of these sex-linked genes carry unusual inheritance such as color blindness, Duchenne muscular dystrophy and hemophilia. (O’Neil, 2012). In the case of the recessive mutation that causes hemophilia, a female has to be the carrier of the mutated allele, since she has the X chromosomes only. If the female carrier of the disease mates with a male who has hemophilia (XhY), there would be a one-quarter chance that they would produce a female offspring that has hemophilia (XhXh). Males though are more susceptible to inheriting the hemophilia trait if the mother is a carrier, because the dominant gene (XH) will prevent the disease. (Simon, 2015). Since males can only have an X and a Y chromosome, there is a 50/50 chance, in this case that the hemophilia trait would be passed on. Every living thing has chromosomes and on these chromosomes are genes, which are “individual units of inheritance that comprise stretches of DNA“(Simon, 2015). Alleles, which are variant forms of these genes, are always found on the X chromosome. If two alleles are identical on the gene for that particular...
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...who have this get it from the gene that causes hemoglobin s. When you have hemoglobin s it means that your red blood cells do not have enough oxygen in them. When the red blood cells do not have enough oxygen they are shaped differently than normal red blood cells. The kind of mutation that causes sickle cell anemia is called a point mutation. When you have a point mutation it affects a very small amount of nucleotides. The mutation that causes sickle cell anemia is a autosomal recessive gene. The parents usually don’t have it so it is a surprise if there child gets a genetic disorder caused by an autosomal...
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...The human body is designed around our genetics and DNA that is passed down to us from our mothers and fathers. Genes outline our physical appearance, health and even our mental capabilities. Our parents have two different types of genes; dominant and recessive. A dominant disorder is passed down to the offspring from a parent with a single mutated allele. A recessive disorder is passed down to the offspring only when both parents have the mutated gene. If one parent is a carrier of the recessive gene then the offspring could also become a carrier of the mutated gene. An example of a recessive inherited disorder is sickle cell disease. Sickle cell disease leads to chronic hemolytic anemia, pain, and organ failure due to abnormal hemoglobin....
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...B1 Genes are found in our chromosomes,which parents pass on to offspring in their sex cells in reproduction. Different versions of the same gene are called alleles, and these can determine features like eye colour, and the inheritance of disorders such as cystic fibrosis. DNA the nucleus controls the activities of a cell. The instructions for how an organism develops are found in the nuclei of its cells Chromosomes Chromosomes are structures found in the nucleus of most cells. They consist of long strands of a substance called deoxyribonucleic acid, or DNA for short. A section of DNA that has the genetic code for making a particular protein is called a gene. The proteins can either be: structural proteins such as the ones found in muscles and hair enzymes, such as proteases and other digestive enzymes Variation Individuals differ in all sorts of ways, even when they are offspring of the same parents. These differences are called variation. Most characteristics, such as height, are determined by several genes working together. They are also influenced by environmental factors. These include: Climate, diet, physical accidents, culture&lifestyle Identical twins Identical twins are genetically the same. They are a good example of the interaction between inheritance and the environment. For example, an identical twin who takes regular exercise will have better muscle tone than one who does not exercise. All of the differences that you see between identical...
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...for PTC taster must be either TT (homozygous dominant) or Tt (heterozygous) I – Results: This experiment aimed to investigate the allele frequency of the PTC taster gene (TAS2R38) in a small population, represented by the students in class. The genotype obtained from genomic analysis (via PCR and gel electrophoresis) confirmed that the genotypic result is consistent with the phenotypic result observed at the beginning of the lab. However, DNA fragments of 3 lab subjects didn’t show up on the gel. The allele frequencies can’t be calculated because the data is insufficient to apply the Hardy-Weinberg equation. There are many factors that might be contributed to the invisibility of these DNA fragments, most likely accidental errors. For example, the DNA wasn’t loaded onto the gel probably, or the DNA for some reason didn’t sink to the bottom of the well, or just simply there was not enough DNA. To determine the genotypic profile of the students PTC gene, DNA samplers from each individual was collected from saliva. Using premade PTC primers (short oligonucleotides), a DNA template that encoded the PTC gene (approximately, 303 bp) was amplified by PCR. After amplification, the produced DNA fragments were digested with Fnu4H1 to identify if the lab subjects have a C or a T at position 785 (PTC taster gene location, Figure 3.) Fnu4H1 (5’ GCTGC 3’) is an enzyme that cuts DNA at specific restriction length polymorphism (RFLP) site present only in wild type alleles and absent in...
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...the idea that the recessive gene can also be strong throughout generations, and somewhat refuting the claim. The frequency table showed that the thumb, earlobe, and hairline all have the dominant trait more frequent. The dominant form frequency for earlobe was 65%, for the thumb was 75%, and hairline had a 55% probability. These numbers are somewhat significant to the opposing recessive form. Which supports the hypothesis because if one or more dominant alleles are present, the probability of the phenotype showing the dominant form is greater. On...
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...codon (base triplet) must be methionine. Then the anticodons on a tRNA with an amino acid comes into the large ribosome unit and matches with a codon. • Describe the relationships between the following terms: o DNA- the heredity material of the cell o Chromatin material- the combination of DNA and proteins that make up the nucleus o Gene- a molecular unit of heredity of a living organism o Chromosome- an organized structure of DNA and protein found in cells • Use the following gene in protein synthesis: TAGGACCATTTTAGCCCC o Show the mRNA. o Show the tRNA. o Name the amino acids that will be placed in the polypeptide chain. (Use the codon table in Ch. 17 of Campbell Biology.) • A gene will direct the making of polypeptide chains, and polypeptide chains form proteins. All enzymes are proteins. Therefore, how would you explain carrying a gene for a trait that does not show up in the offspring? Genes can be dominant and recessive. A recessive gene may not carry over into offspring, where as a dominant gene is more likely to carry over. An example would be blue or green eyes and brown eyes. Green or blue eyes are recessive and brown are dominant. A child is more likely to have brown eyes than blue/green if one parent has brown eyes. • In order for DNA to pass genetic information to the next...
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