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Genetic Disorders and Mutations. There are two main types of mutations. 1. Gene mutations —happen during DNA replications—A change to the original DNA sequence 2. Chromosome mutations —happen during meiosis—Changes the number or location of genes. Gene Mutations.
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There are two main types of mutations • 1. Gene mutations—happen during DNA replications—A change to the original DNA sequence • 2. Chromosome mutations—happen during meiosis—Changes the number or location of genes
Gene Mutations • Point mutations: substitute one nucleotide for another • ATTACC AATACC • Frameshift mutations: the insertion or deletion of a nucleotide • ATTACC ATACC (deletion) • ATTACC ACTTACC (insertion) • These will affect all the codons that come after the insertion or deletion
Chromosome Mutations • Duplication: changes the size of chromosomes and results in multiple copies of a single gene • Translocation: pieces of non-homologous chromosomes exchange segments • Nondisjunction: Chromosomes do not separate correctly during anaphase, resulting in 1 or 3 chromosomes rather then 2 per cell.
Genetic Disorders are coded in Disease Alleles created by mutations • Like all alleles, they can be: • Dominant • Recessive • Or sex-linked • That means that a person with a single dominant disease allele will have the disease! • We trace family histories of diseases in charts called pedigrees
