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Mutations Ch-Ch-Ch-Changes. Variation & Speciation Variation also allows sexually reproducing organisms to adapt to a changing environment. The mechanism.

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Presentation on theme: "Mutations Ch-Ch-Ch-Changes. Variation & Speciation Variation also allows sexually reproducing organisms to adapt to a changing environment. The mechanism."— Presentation transcript:

1 Mutations Ch-Ch-Ch-Changes

2 Variation & Speciation Variation also allows sexually reproducing organisms to adapt to a changing environment. The mechanism of mutation in DNA generates variation with natural selection of individuals in populations to produce new species.

3 DNA mRNA Transcription How Mutation Works Cell Polypeptide (protein) Translation Ribosome ©1998 Timothy G. Standish

4 Mutation Mutation = Change Biologists use the term “mutation” when talking about any change in the genetic material. Not all result in a change in phenotype.

5 Macromutations Four major types of Macromutations are recognized: 1Deletions - Loss of chromosome sections 2Duplications - Duplication of chromosome sections 3Inversions - Flipping of parts of chromosomes 4Translocations - Movement of one part of a chromosome to another part

6 Macromutation - Deletion Chromosome Centromere A B C D E F G H Genes E F A B C D G H

7 Macromutation - Duplication Chromosome Centromere A B C D E F G H Genes A B C D E F E F G H E F Duplication

8 Macromutation - Inversion Chromosome Centromere A B C D F E G H Genes A B C D E F G H Inversion

9 Macromutation - Translocation A B E F C D G H Chromosome Centromere Genes A B C D E F G H

10 Micro or Point Mutations 1 Additions - Addition of one or two nucleotides 2 Deletions - Loss of one or two nucleotides

11 Micro Mutations 5’ AGUC-AUG-ACU-UUG-GUA-GUU-GAC-UAG-AAA 3’ 3’ AGTTCAG-TAC-TGA-AAC-CAT-CAA-CTG-ATCATC 5’ 3’ AGTTCAG-TAC-TGA-ACA-CCA-TCA-ACT-GATCATC 5’ 5’ AGUC-AUG-ACU-UGU-GGU-AGU-UGA-CUAGAAA 3’ MetThrCys Gly Ser MetThrVal Leu Micro-mutations tend to have a dramatic effect on proteins as all codons down stream from the mutation are changed and thus code for different amino acids. As a result, the length of the polypeptide may also be changed as a stop codon will probably come at a different spot than the original stop codon.

12 Mutations Are Uncommon Cells have many different mechanisms for preventing mutations These mechanisms make mutations very uncommon Even when point mutations occur in the DNA, there may be no change in the protein coded for

13 Mutagens Mutations often occur naturally as a result of random errors in replication. Environmental Factors Radiation - X-ray -Ultraviolet radiation Chemicals - Mustard gas - Chloroform

14 Val Mutant  -globin H2NH2N OH C O H2CH2C H C CH 2 C O Acid Glu Normal  -globin TCT Normal  -globin DNA H2NH2N OH C O H3CH3C H C CH CH 3 Neutral Non-polar AGA mRNA TCA Mutant  -globin DNA AGU mRNA The Sickle Cell Anemia Mutation

15 Weakness Tower skull Impaired mental function Infections Especially Pneumonia ParalysisKidney failure Rheumatism Sickle Cell Anemia: A Pleiotropic Trait Mutation of base 2 in  globin codon 6 from A to T causing a change in meaning from Glutamate to Valine Mutant  globin is produced Red blood cells sickle Heart failure Pain and Fever Brain damage Damage to other organs Spleen damage Anemia Accumulation of sickled Cells in the spleen Clogging of small Blood vessels Breakdown of Red blood cells

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