2 Any change in the DNA base sequence What is a mutation?Any change in the DNA base sequence
3 What are the two different classes of mutations? Gene MutationsChromosomal Mutations
4 What is a gene mutation?A change in the base sequence of one gene
5 What causes gene mutations? Errors in DNA replicationChemicalsUV/X-ray Radiation
6 Types of Gene Mutations SubstitutionDeletionInsertionOriginal DNA Strand
7 Two types of Gene Mutations Point mutationA change in ONE nitrogenous base, the overall number of bases stays the same (Substitution)Frame shift mutationA change in the number of overall nitrogenous bases in the genetic code (Insertion or Deletion)
8 Substitution Mutation Substitution – One nitrogenous base is substituted for another.
9 Deletion and Insertion Mutations Deletion – One or more nitrogenous bases are removedInsertion – Extra nitrogenous bases are added to the genetic code.
13 How can gene mutations be passed down to future offspring? ONLY IF THEY OCCUR IN THE SEX CELLS
14 What are some characteristics of gene mutations? They can be dominant or recessiveThey can occur on autosomal chromosomes (pairs 1-22) or sex chromosomes (pair 23) People that are heterozygous for a recessive genetic disorder are called carriers Carriers have one normal allele and one diseased allele; They do not show symptoms for the disease but may pass the allele to future offspring
16 Genetic Diseases caused by gene mutations: Cystic FibrosisFaulty gene produces adefective protein that does not allow for the properremoval of mucous lining the cells of the lung and GItract.
17 Gene Mutations: Tay-Sachs Disease Faulty gene produces a defective enzymewhich cannot help remove fat from nerve cells.
18 Sickle-Cell Anemia:One base is substituted for another and this causesthe production of a distorted hemoglobin molecule(protein) which cannot function properly.
19 What do these three gene mutations have in common? They all affect the shape of proteins!! If we changethe shape of proteins (enzymes) they will notfunction properly and this will affect our phenotype.
20 How do we trace/identify gene mutations in a population or family? Pedigree Charts: - A diagram that shows the presence or absence of a particular trait through each generation.Genetic Testing: Ability to diagnose vulnerabilities to various genetic disorders