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Learn about genetic mutations, including Crouzon Syndrome, Harlequin-type ichthyosis, Neurofibromatosis, Ehlers-Danlos Syndrome, and more. Explore different types of mutations and their effects on organisms.
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Brainstorm…… • Explain to the best of your ability what a “genetic mutation” means to you……. (use all of your prior knowledge of biology!)
Crouzon Syndromegenetic disorder, skull bones fuse, 1-25,000 are affected
Symptoms: • Survival of about a month • Skin is hard with thick scales • Dehydration occurs quickly because the skin can not maintain water • Body temperature problems • Difficulty breathing due to skin restriction
Neurofibromatosis • The previous picture is of a 32 year old male named Huang who lives in China • Aprox. 50 lb. tumor • Genetic disease that effects the development and growth of nerve tissue • Tumors may be removed but also very likely to return • Huang has currently had 2 surgeries to remove his tumors
Elastic Baby!Ehlers-Danlos Syndrome (genetic disorder of connective tissue)
Genetic Mutations A change in the DNA of an organism
Mutations • 1. Germ cell mutation– mutations in gametes (doesn’t affect organism) • 2. Somatic mutations– mutation in an organisms body cells, i.e. can affect the organism ex: human skin cancer, leukemia • 3. Lethal mutations– cause death often before birth (some may form phenotypes that are beneficial natural selection)
Chromosomal Mutations(change in structure of chr. Or loss of entire chromosome • 1. deletion: loss of piece of chr. (chr breakage) • 2.inversion: chr. Segment breaks off and then reattaches in reverse orientation to the same chromosome • 3.translocation: chr. Piece breaks off and reattaches to another non homologous chr. • 4. nondisjunction: failure of chr. To separate from its homologue during meiosis (when this occurs 1 gamete lacks the chr. entirely
NONDISJUNCTION • *
Gene Mutations • May involve large segments of DNA or a single nucleotide within a codon! • point mutation: substitution, addition, or removal of a single nucleotide
Point mutation (substitution) One nucleotide in a codon is replaced with a different nucleotide resulting in a new codon
Sickle Cell Anemia(Point mutation) • Substitutes adenine for thymine in a single DNA codon • Occurs in 1 in 500 African American in U.S • Heterozygous generally healthy
INSERTION & DELETION • Mutations tend to be more serious • Remaining codons after are all incorrectly grouped resulting in FRAME SHIFT MUTATION!