Download
1 / 20
200 likes | 203 Views
Learn about molecular genetics mutations, including point mutations, insertions, and deletions, and their causes. Explore the impact of mutations on Hox genes, body-cell vs. sex-cell mutations, and different types of point mutations and their associated diseases. Discover frameshift mutations, duplications, expanding mutations, and visible mutations in genetic disorders.
E N D
Molecular Genetics Mutations • A permanent change that occurs in a cell’s DNA is called a mutation. • Types of mutations • Point mutation • Insertion • Deletion
Molecular Genetics Causes of Mutation • Can occur spontaneously • Chemicals and radiation also can damage DNA. • High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.
Molecular Genetics Hox Genes • Hox genes are responsible for the general body pattern of most animals.
Molecular Genetics Body-cell v. Sex-cell Mutation • Somatic cell mutations are not passed on to the next generation. • Mutations that occur in sex cells are passed on to the organism’s offspring and will be present in every cell of the offspring.
A Point Mutation is caused when a single base is changed in the DNA strand. 3 types: Nonsense: Change causes a Stop codon, shortening the protein Missense: Changes to a different amino acid, may cause loss of function Silent: Base changes codon to the same Amino Acid, so not seen. Point Mutation
Missense A substitution Mutation THE BIZ FAT CAT ATE THE WET RAT Results: Changes a single Amino acid Disease: Achondroplasia (Dwarfism)
NONSENSE Substitution THE BIG RAT The substitution prematurely stopped the code. DISEASE: Muscular Dystrophy
Caused by adding or a deleting a base which throws off the 3 base coding frame. Example: Dowling–Degos Disease - over pigmentation - Looks like big freckles Frameshift Mutation(Insertions and Deletions)
DELETION Removal of a single base THB IGF ATC ATA TET HEW ETR AT Called a frameshift mutation. Throws off the 3 base reading frame causing a new amino acid sequence that makes the incorrect protein DISEASE: Cystic fibrosis
INSERTION Frameshift mutation: Adding a base – Throwing off the reading frame THE BIG ZFA TCA TAT ETH EWE TRA T DISEASE: CROHN’s DISEASE
DUPLICATION Extra copy/repeat of a segment of DNA. THE BIG CAT BIG CAT ATE THE WET RAT Disease: Charcot-Marie-Tooth Disease
EXPANDING MUTATION(Tandem Repeats) A duplication that keeps occurring. Lengthening the protein until almost unuseable THE BIG BIG FAT CAT THE BIG BIG BIG FAT CAT THE BIG BIG BIG BIG FAT CAT DISEASE: Hunnington’s Disease
Real Mutations Visible mutations usually required more than one genetic mutation.
Down Syndrome: Trisomy 21 Nondisjunction event causing the 21st chromosome pair to not separate during meiosis (Gamete formation)
Multi X female (Nondisjunction during egg formation – X chromosomes fail to separate)
Muscle protein gene mutation. Causes double the muscle tissue to form resulting in one buff dog… or super strong German Toddler
