MELC 16 Mutation

• mutation - a natural process that changes the DNA structure of an organism, resulting to new characteristic. changes in genetic code
• spontaneous mutation - something went wrong in the process replicating or forming the gametes
• induced mutation - caused by the environment: radiation, chemicals, high temperatures, microbial infections
• types of mutation

  gene mutation - only a single gene is affected during the replication of DNA

  chromosomal mutation - any change in the number or structure of a chromosome
• point mutation - an incorrect nucleotide is substituted for the correct nucleotide

  example: sickle cell anemia
• frame shift mutation - involves the insertion or deletion of a nucleotide in the DNA sequence that changes codons. The shift may produce different amino acids and proteins.

  examples:

  beta thalassemia (insertion) - is a blood disorder that reduces the production of hemoglobin.

  cystic fibrosis (deletion) - is an inherited disease characterized by the buildup of thick, sticky mucus that can damage many of the body's organs.
• genes - basic unit of heredity paired from parents to offspring. Basically, made up of sequences of DNA and found within the chromosomes.
• chromosomes - structure found inside the nucleus of a cell, and it     is made up of proteins and DNA organized into genes.
• deletion - one or more gene is removed.

  
  

  example: turner syndrome (loss of 2nd sex chromosome)
• inversion - when a segment of genes flips end-to-end on the chromosome, inversion occurs

  example: four-ring syndrome
• translocation - genes are swapped with another chromosome

  example: down syndrome
• human karyotype - an individual's complete set of chromosomes
• cri du chat - is caused by the deletion of part of the short arm of chromosome 5