MUTATIONS

1. MUTATIONS Changes in DNA that affect genetic information

2. DNA Mutations • Any change in DNA sequence • Can be caused by errors in replication, transcription, cell division or by external agents

3. Point Mutations • A change in a single base pair in DNA • This change can change the entire structure of a protein due to the change in a single amino acid.

4. Point Mutations • Changes in one or a few nucleotides • Substitution • THE FAT CAT ATE THE RAT • THE FAT HAT ATE THE RAT • Insertion • THE FAT CAT ATE THE RAT • THE FAT CAT XLW ATE THE RAT • Deletion • THE FAT CAT ATE THE RAT • THE FAT ATE THE RAT

5. Frameshift Mutations • A single base change added or deleted from the DNA strand • Shifts the reading of the codons by one base

6. Frameshift Mutations • Shifts the reading frame of the genetic message so that the protein may not be able to perform its function. • Insertion • THE FAT CAT ATE THE RAT • THE FAT HCA TAT ETH ERA T • Deletion • THE FAT CAT ATE THE RAT • TEF ATC ATA TET GER AT H H

7. Chromosome Mutations • Changes in number and structure of entire chromosomes • Original Chromosome ABC * DEF • Deletion AC * DEF • Duplication ABBC * DEF • Inversion AED * CBF • Translocation ABC * JKL GHI * DEF

8. Significance of Mutations • Most are neutral • Eye color • Birth marks • Some are harmful • Sickle Cell Anemia • Down Syndrome • Some are beneficial • Sickle Cell Anemia to Malaria • Immunity to HIV

9. What Causes Mutations? • There are two ways in which DNA can become mutated: • Mutations can be inherited. • Parent to child • Mutations can be acquired. • Environmental damage • Mistakes when DNA is copied

10. Mutations in Sex Cells • May produce a new trait or may result in a protein that does not work correctly • In some rare cases, it may have a positive effect • Can be passed on to offspring

11. Mutations in Body Cells • If a body cell’s DNA is changed, this mutation would not be passed on to offspring. • It may cause problems for the individual • Damage to a gene may impair the function of the cell. • Can result in the cell growing and dividing rapidly, causing cancer.

12. Causes of Mutations • Mutagen – any agent that can cause a change in DNA • Include radiation, chemicals and even high temperatures

13. Chromosome Mutations • Down Syndrome • Chromosome 21 does not separate correctly. • They have 47 chromosomes in stead of 46. • Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of intelligence.

14. Chromosome Mutations • Cri-du-chat • Deletion of material on 5th chromosome • Characterized by the cat-like cry made by cri-du-chat babies • Varied levels of metal handicaps

15. Sex Chromosome Abnormalities • Klinefelter’s Syndrome • XXY, XXYY, XXXY • Male • Sterility • Small testicles • Breast enlargement

16. Sex Chromosome Abnormalities • XYY Syndrome • Normal male traits • Often tall and thin • Associated with antisocial and behavioral problems

17. Sex Chromosome Mutations • Turner’s Syndrome • X • Female • sex organs don't mature at adolescence • sterility • short stature

18. Sex Chromosome Mutations • XXX • Trisomy X • Female • Little or no visible differences • tall stature • learning disabilities • limited fertility