Human Mutations

Mutations If an error occurs during DNA replication (also known as a gene mutation) Something goes wrong with meiosis leading to chromosomal abnormalities

Gene Mutations Point mutation: substitution, addition, or removal of a single nucleotide Substitution results in a new codon Inserts or deletions result in a frame shift – causing a new codon

Non-disjunction Failure of chromosome to separate from its homologue during meiosis; one gamete receives an extra copy and the other one lacks a copy

Deletions Loss of a piece of chromosome due to breakage

Inversion A segment breaks off and reattaches in reverse order

Translocation Chromosome piece breaks off and reattaches to another nonhomologous chromosome

Normal Female

Normal Male

Turner’s Syndrome

Down’s Syndrome

Klinefelter’s Syndrome