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Published byRandall Jenkins Modified over 8 years ago
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Objective: I can explain how genes jumping between chromosomes can lead to evolution. Chapter 21; Sections 21.4-21.5; Pgs. 434-442 Genomes: Connecting Advanced Genetics & Biotechnology to prove Evolution
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Parts of the genome: collection of all DNA/genes in a given organism Part of DNA that will encode for proteins = Exons Part of DNA that is transcribed, but… …spliced out and recycled = introns …utilized for regulation = ncRNA (help regulation) Parts of DNA never transcribed = Regulatory sequences (operons, enhancers: control elements, etc.) All of the above = ~42.5% of genome
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Types of DNA Most of DNA are sequences that do nothing but repeat or move around, but may have evolutionary significance
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Types of ncDNA (non-coding DNA) Pseudogenes: encoded for protein in past but gained mutations so non-functional Repetitive DNA: multiple copies of segments of DNA …sounds like…? STR = short tandem repeats Transposable elements: segments of DNA that move from one location to another “jumping genes” Discovered by Barbara McClintock (nobel)
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Types of Transposable Elements Transposons: DNA intermediate…means… Retrotransposons: RNA intermediate; requires Reverse transcriptase (encoded by transposon) How does transposition differ from translocation? Copy & paste vs. Cut & paste
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Multigene Families = collection of 2 or more identical/very similar genes based on sequence If consist of identical DNA (usually tandem) Usually for purpose of massive production (i.e. rRNA protein ribosomes) If consist of nonidentical DNA (may be far apart) Usually function together can indicate evolutionary history
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Genome Changes Lead to Evolution Duplication of entire chromosome sets Not just n or 2n, but 3n, 4n, 5n, etc. = Polyploidy from Nondisjunction (LOTS) Different chromosomes # = new species (more later) Also, alteration of chromosome structure new species…alteration comes from…?
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Sources of Genome Evolution = Chromosomal Mutation Duplications, Inversions, Deletions, Translocations AND Transpositions If altered chromosomes are functional and provide advantage, then passed on evolutionary history of genome
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Tracking Evolution of Genes Examine sequences to see how similar Multigene family with green = pseudogene (similar sequences)
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Result of “Jumping Genes” Transposons Besides random mutations from polymerase May inactivate gene if move to repressed… May activate gene if move to promoted… May reduce function if interrupt… May enhance function if made more… BUT only evolve if…
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Summary of Biotechnology http://www.youtube.com/watch?v=ebS WG1QmxnY http://www.youtube.com/watch?v=ebS WG1QmxnY Consider the global and social impacts
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