1. Genetic Mutations Biology Chapter 12.4 Wilson

2.  Describe the different types of genetic mutations.  Describe the different types of chromosomal mutations.  Explain how mutations can lead to genetic diversity. Objective

3.  A permanent change in genetic material  A change in the DNA sequence  As a cell copies its DNA before dividing, a "typo" occurs every 100,000 or so nucleotides  About 120,000 typos each time one of our cells divides Mutations

4.  Commonly the terms "mutant" and mutation" are used to describe something undesirable or broken  Not all mutations are bad, most have no effect  When variations occur within genes, there is more often a consequence, but rarely causes death or disease  Generates new variations that can be an advantage  Gives rise to variations that are neither good nor bad, just different Mutations Click

5.  Exogenous factors (outside): environmental factors such as:  Sunlight  Radiation  Smoking  Etc...  Endogenous factors (inside): errors during DNA replication  Change in protein being made or not made  Can lead to toxic by-products  Alter cellular metabolism What Causes Mutations? Radiation VideoVideo

6.  Genetic Mutations Genetic Mutations  Point Mutation  Silent  Missense  Nonsense  Frameshift Mutation  Deletion  Insertion  Chromosomal Mutations Chromosomal Mutations  Deletion  Duplication  Inversion  Translocation Types of Mutations

7.  Point Mutation – Substitution of one Nucleotide  Silent – codon codes for the same amino acid  Nonsense – codon codes for a stop! BAD NEWS BEARS  Missense – codon codes for a different amino acid  Nonsense and Missense will not produce the same or healthy protein or enzyme  Point Mutations Point Mutations Genetic Mutations

8.  Frameshift mutations –  Shift the reading frame of codons from the point of mutation on  Changes multiple amino acids  More dramatic change to a protein than a point mutation  Insertion – adds nucleotide (s)  Deletion – deletes a nucleotide(s) Genetic Mutations

9.  Insertion – addition of a nucleotide, shifts the reading frame to the right, changes how the codons are “read”… think of it as adding letters to a sentence Frameshift Mutation DNA like sequence Codon Amino Acids

10.  Deletion – deletes one or more nucleotides, which shifts the reading frame to the left of the change Frameshift Mutations DNA like sequence Codon Amino Acids

11.  Kahoot Genetic Mutation Review

12.  Effect entire sections of genes not just the one base pair or a set of codons  Have similar names as point mutations but they affect a number of genes that are made up of hundreds of base pairs  Many of these occur as gametes are being formed  Can be the most severe causing severe birth defects or even death Chromosomal Mutations

13.  During meiosis chromosomes may not split properly, called nondisjuction.  Results is a child having a greater or frewer number of chromosomes.  Children with these types of mutations seldom live into adulthood  Some common mutations are:  Down syndrome (trisomy 21) – having a third chromosome 21 Down syndrome  Patau syndrome (trisomy 13) – having a third chromosome 13Patau syndrome  Edward's syndrome (trisomy 18) – having a third chromosome 18 Edward's syndrome Chromosomal Mutations

14.  Nondisjunction of the sex chromosomes (X or Y chromosome)  Klinefelter syndrome: XXY males, XYY males, Trisomy X: XXX females, Monosomy X (Turner's syndrome) Klinefelter syndrome  The only viable monosomy in humans - women with Turner's syndrome have only 45 chromosomes!!!Turner's syndrome  These types of chromosomal mutations can be seen in a human karyotype. Chromosomal Mutations

15.  Deletion – a removal of a whole set of genes from a chromosome Chromosomal Mutations

16.  Duplication – the copying of a whole set of genes from a chromosome Chromosomal Mutations

17.  Inversion – the reversal of the gene order on a chromosome Chromosomal Mutations

18.  Translocation – genes from one chromosome are moved to another chromosome Chromosomal Mutations

21.  Review Review Chromosomal Mutations