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Unformatted text preview: 9/20/09 1 MICRO-EVOLUTION AND HOW IT IS MEASURED MICRO EVOLUTION 1. Microevolution 2. Gene Pool and Breeding Population . CAUSES OF MICRO-EVOLUTION 1. Mutation 2. Gene fow & or migration 3. Founder e¡¡ect 4. Genetic dri¡t 5. Bottleneck e¡¡ect 6. Cultural ¡actors 7. Natural selection MEASURING EVOLUTIONARY CHANGE 1. Kinds o¡ Natural Selection 3. Application o¡ the Hardy-Weinberg Equation To Measure Evolution SICKLE CELL HEMOGLOBIN & NATURAL SELECTION 1. Physiological e¡¡ects 2. Mutation & Genetic inheritance 3. Malaria and the origin o¡ sickle cell Hb. 4. Cultural Modi¢cation MICRO-EVOLUTION AND HOW IT IS MEASURED MICRO EVOLUTION 1. Microevolution refers to changes in gene frequency or any heritable trait within a single breeding population. That is, microevolution refers to changes occurring below the level of species. If the changes results in speciation is considered macroevolution. 2. Bacterial strains that have become resistant to antibiotics, or color changes in moths over time are all examples of microevolution 3. Breeding Population is a group of organisms that interbreed with each other and all share a common gene pool. i.e. a group of individuals that are potential mates for one another. CAUSES OF MICRO-EVOLUTION : MUTATIONS Harmful if a mutation changes the function of the protein made by the gene is be harmful. Despite the fact that gene mutations that could cause a genetic disorder are repaired by the DNA repair system of the cell, about 70 percent of harmful mutations have damaging effects. Bene¢cial mutations Some mutations have a positive effect. For example, a speci¡c 32 base pair deletion in human CCR5 (CCR5- Δ 32) confers HIV resistance to homozygotes and delays AIDS onset in heterozygotes. The CCR5 mutation is more common in those of European descent, but the cause for this mutation is related to several historical events experienced by European populations. 9/20/09 2 CAUSES OF MICRO-EVOLUTION : MUTATIONS Mutation is a random alteration in the DNA sequence of a gene during cell division due to exposure to mutagens (such as high levels of ionizing radiation, X-rays). CAUSES OF MICRO-EVOLUTION : MUTATIONS Mutagenic agents (i.e. x0rays, gamma rays, some chemicals) can also result in chromosome mutations like inversions, translocation, duplications and de¡ciencies CAUSES OF MICRO-EVOLUTION : MUTATIONS If a mutation is present in a germ cell, it can give rise to...
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- Spring '08