• A genome is the full set of genetic information that an organism carries in its DNA. • The study of any genome starts with the analysis of chromosomes. • Chromosomes are bundles of DNA and protein found in the nuclei of eukaryotic cells. Fruit fly chromosomes How are chromosomes analyzed? • To study chromosomes, scientists photograph chromosomes in mitosis and arrange them in a picture known as a karyotype. • A karyotype shows the complete diploid set of chromosomes grouped together in pairs, arranged in order of decreasing size. • A typical human karyotype contains 46 chromosomes arranged in 23 pairs. 1. Define What is a karyotype? Let’s Analyze! Down’s Syndrome • Called TRISOMY 21 • genetic disorder that occurs in approximately 1 of 800 live births • SYMPTOMS • • • • • Cognitive impairment Learning disabilities Develpmental delays Low muscle tone (infancy) Characteristic facial features • Heart defects • Other health issues • CAUSES Non-disjunction of the 21st chromosome Klinefelter’s Syndrome • Klinefelter’s syndrome occurs in about 1 out of 1,000 males. • XXY (extra copy of an X chromosome) • SYMPTOMS • • • • • Not always noticiable symptoms Large hips Small breasts Fat around the abdomen Small testicles • CAUSES • Non-disjunction of the sex chromosomes in either sperm or egg How is DNA fingerprinting used to study genomes? • No two individuals, except identical twins, are genetically identical. • DNA fingerprinting analyzes sections of DNA that may have little or no function but that vary widely from one individual to another. . (contd.) HOW IS DNA Fingerprinted? 1. DNA is cut by restriction enzymes 2. scientists use gel electrophoresis to separate and analyze the differently sized fragments. 3. Scientists compare the BANDS made 2. Describe How do scientists separate DNA? DNA fingerprinting is used to study genomes? Teachers…Click on the following link http://www.rocklin.k12.ca.us/staff/avrudny/Scie nce/Advanced_Biology/Unit_8/DNA_Fingerprint ing_Activity.pdf Focus on the bottom of the activity only! Crime Scene Analysis CASE 1 and CASE 2 • The Human Genome Project was an international effort to sequence all 3 billion base pairs of human DNA. • Other important goals included sequencing the genomes of model organisms to compare to human DNA, developing technology to support the research, exploring gene functions, studying human variation, and training future scientists. • Today, multiple copies of the human genome, along with those of hundreds of other organisms, are available to the public. 3. Explain What are some of the goals of the Human Genome Project? Human beings have always tried to improve the plants and animals they use for food, work, and companionship. Selective breeding describes the process by which humans allow only those animals with certain characteristics to produce the next generation. Two Methods of Selective Breeding 1.Hybridization 2.Inbreeding Crossing dissimilar individuals together to bring together the best of both organisms Continued breeding of individuals with similar characteristics What are transgenic organisms? • It is possible to construct organisms that are transgenic, containing genes from other species. • Genetic engineers can now produce transgenic plants, animals, and microorganisms. By examining the traits of a genetically modified organism, it is possible to learn about the function of the transferred gene. • This ability has contributed greatly to our understanding of gene regulation and expression. What is recombinant DNA? Recombinant DNA consists of DNA molecules that have been taken from two sources and then recombined. Recombinant-DNA technology makes it possible to construct DNA molecules with nearly any combination of genes. Cloning • Clone – member of a population of genetically identical cells First dog successfully cloned Infer Using the example of the sheep cloning, why wouldn’t the cloned lamb resemble its foster mother?
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