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Published byDina Reeves
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What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes (eggs & sperm) and be passed to offspring
Are Mutations Helpful or Harmful? Mutations happen regularly Almost all mutations are neutral Chemicals & UV radiation cause mutations Many mutations are repaired by enzymes
Are Mutations Helpful or Harmful? Some type of skin cancers and leukemia result from somatic mutations Some mutations may improve an organism’s survival (beneficial)
Types of Mutations
Chromosome Mutations May Involve: Changing the structure of a chromosome The loss or gain of part of a chromosome
Chromosome Mutations Five types exist: Deletion Inversion Translocation Nondisjunction Duplication
Deletion Due to breakage A piece of a chromosome is lost
Chromosomal Deletion One or more genes are removed Causes: Wolf-Hirschhorn syndrome (severe mental retardation) cri du chat syndrome (mewing sounds, mental retardation)
Inversion Chromosome segment breaks off Segment flips around backwards Segment reattaches
Chromosomal Inversion a segment of genes flip end-to-end on the chromosome Causes: Four-Ring Syndrome (cleft pallate, club feet, testes don’t descend)
Duplication Occurs when a gene sequence is repeated
Chromosomal Duplication A segment of genes is copied twice and added to the chromosome Causes: Charcot–Marie–Tooth disease (high arched foot, claw feet, confined to a wheelchair)
Translocation Involves two chromosomes that aren’t homologous Part of one chromosome is transferred to another chromosomes
Chromosomal Translocation Material is swapped with another chromosome Causes: Burkitt’s Lymphoma (cancer of the lymph nodes, in children)
Nondisjunction Failure of chromosomes to separate during meiosis Causes gamete to have too many or too few chromosomes
Nondisjunction Chromosomes FAIL TO SEPARATE during meiosis Meiosis I Nondisjunction Meiosis I Nondisjunction Meiosis II Nondisjunction Meiosis II Nondisjunction
Nondisjunction Produces gametes (and therefore a baby) with one missing chromosome or one extra chromosome
Nondisjunction (in Meiosis II)
Down Syndrome Cause: Nondisjunction of chromosome 21 Three copies of chromosome 21 = “TRISOMY 21”
Trisomy 21 - Down Syndrome
Sex Chromosome Abnormalities Klinefelter’s Syndrome XXY, XXYY, XXXY Male Sterility Small testicles Breast enlargement
Sex Chromosome Abnormalities XYY Syndrome Normal male traits Often tall and thin Associated with antisocial and behavioral problems
Sex Chromosome Mutations Turner’s Syndrome X Female sex organs don't mature at adolescence sterility short stature
Sex Chromosome Mutations XXX Trisomy X Female Little or no visible differences tall stature learning disabilities limited fertility
Gene Mutations Change in the nucleotide sequence of a gene May only involve a single nucleotide May be due to copying errors, chemicals, viruses, etc.
Types of Gene Mutations Include: Point Mutations Substitutions Insertions Deletions Frameshift
Point Mutation Change of a single nucleotide Includes the deletion, insertion, or substitution of ONE nucleotide in a gene
Point Mutation Sickle Cell disease is the result of one nucleotide substitution Occurs in the hemoglobin gene
Frameshift Mutation Inserting or deleting one or more nucleotides Changes the “reading frame” like changing a sentence Proteins built incorrectly
Frameshift Mutation Original: The fat cat ate the wee rat. Frame Shift (“a” added): The fat caa tet hew eer at.
Amino Acid Sequence Changed
Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes.
Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring, only to descendant cells)
DNA Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA.
Human Genetic Mutations
Types of Mutations.
8.7 – Mutations. Key Concept Mutations are changes in DNA that may or may not affect phenotype. mutated base.
HW # 80- Make cookies for the Cookie Mutation Lab Warm up What are the different types of mutations? How are mutations related to evolution? Place your.
Mutations. What Are Mutations? A change in the structure or amount of an organisms genetic material This mutation can be a tiny change in DNA structure.
MUTATIONS. WHAT ARE MUTATIONS? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes.
In your journal take down 5 facts while watching the video.
Mutations. What Are Mutations? MUTATION = A change in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur.
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