1. Mutations A change in the DNA structure There are two categories of mutations

2. Gene Mutation 1. A change in the DNA 2. A change in the sequence of nitrogenous bases 3. Mutagens can cause the change

3. What’s Happened to the DNA? Both had one base substituted for another.

4. How was the DNA changed in these examples?

5. Comparing Gene Mutations

6. What can a changed protein do to an organism? Additional Ways DNA Mutated

7. Mutation: Frameshift 1. Changes the reading of the DNA 2. Results in the formations of new mRNA codons leading to a change in the polypeptide structure 3. Types are: insertion or deletion

8. Identify the category and type of mutation affecting this strand of DNA 1. AUGCCGUACCUUAUGGCUG 2. AUGC_GUACCUUAUGGCUG 1. AUGCACGUACCU… 2. AUGCGUACCUUA… Mutated Strand reads: Notice that the reading of the DNA will be shifted. Hence, these are frameshift mutations. The mRNA when translated will produce a different amino acid sequence. A

9. Human Red Blood Cells 1. Contain the protein, hemoglobin (Hb) 2. O 2 binds to Hb = oxygenated blood 3. Red Blood Cells are doughnut shaped cells

10. Sickle Cell Anemia 1. RBC’s are “sickled shape” 2. Hemoglobin protein has been altered -shape has changed 3. Cells stick to each other; Oxygen binding capacity has been altered. 4. Circulatory problems arise Why?

11. Normal Hemoglobin: Valine-Histidine-Leucine-Threonine-Proline-Glutamic Acid-Glutamic Acid Abnormal Hemoglobin: Valine-Histidine-LeucineThreonine-Proline-Valine-Glutamic Acid Sickle Cell Anemia had change in the polypeptide chain: Glutamic acid is changed to Valine Why??????? How can this be??????????????

12. Change Affects Codon Normal Hb DNA: CTT mRNA: GAA Amino Acid: Glutamic acid …Proline-Glutamic Acid- Glutamic Acid… Sickle Hb DNA: CAT mRNA: GUA Amino Acid: Valine …Proline-Valine-Glutamic Acid… What type of mutation caused the altered hemoglobin? A Point Mutation – base substitution

13. This is normal structure

14. Codon Change Affects Protein Structure

15. Chromosomal Mutation Alterations in chromosome number and/or structure

16. Figure 8.23A, B Deletion Duplication Inversion Homologous chromosomes Reciprocal translocation Nonhomologous chromosomes Structural Chromosomal Mutations Read 8.22, 8.23, 8.24

17. Chromosome Number for a Species Species # of chromosomes Species # of chromosomes Fruit fly8Human46 Rye14Ape48 Guinea Pig16Sheep54 Dove16Horse64 Snail24Chicken78 Earthworm32Carp104 Pig40Butterflies~380 Wheat42Fern~1200

18. Does the embryo have the correct number of chromosomes?

19. Egg cell Sperm cell Chromosome Number Mutation zygote Does the zygote have the correct number of chromosomes?

20. LE 13-10 Key Maternal set of chromosomes Paternal set of chromosomes Possibility 1 Possibility 2 Combination 2 Combination 1 Combination 3 Combination 4 Daughter cells Metaphase II Two equally probable arrangements of chromosomes at metaphase I

21. LE 13-7 Homologous pair of chromosomes in diploid parent cell Interphase Homologous pair of replicated chromosomes Chromosomes replicate Meiosis I Diploid cell with replicated chromosomes Sister chromatids Meiosis II Homologous chromosomes separate Sister chromatids separate Haploid cells with replicated chromosomes Haploid cells with unreplicated chromosomes

22. A karyotype: a photographic inventory of an individual’s chromosomes A karyotype: a photographic inventory of an individual’s chromosomes To study human chromosomes microscopically, researchers stain and display them as a karyotype ◦A karyotype usually shows 22 pairs of autosomes and one pair of sex chromosomes Additional information 8.19-20

23. Preparation of a karyotype Figure 8.19 Blood culture 1 Centrifuge Packed red And white blood cells Fluid 2 Hypotonic solution 3 Fixative White Blood cells Stain 4 5 Centromere Sister chromatids Pair of homologous chromosomes

24. This karyotype shows three number 21 chromosomes An extra copy of chromosome 21 causes Down syndrome Let’s look at this Karyotype Figure 8.20A, B

25. The chance of having a Down syndrome child goes up with maternal age…why? Figure 8.20C

26. Beginning the Karyotype

27. Karyotype Lab 1. You will simulate the karyotyping task. 2. You will create a karyotype and determine the gender and developmental status of the baby. 3. You must carefully cut out all chromosomes and correctly match them up by: a.Size of chromosome b.Location of centromere c.Banding pattern on chromosome

28. Finished Karyotype

29. Another Karyotype Male or Female?