mutations pp. 224-226, 231. mutation a change in a genetic trait either 1) chromosomal or 2) gene...
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MUTATIONS
pp. 224-226, 231
MUTATIONA change in a genetic traitEither 1) chromosomal or 2) gene mutationGerm cell (gametes) or somatic cell (body)
Germ cell mutations can be inherited and somatic cell mutations result in cancers
Can be lethal (deadly) even before birth
CHROMOSOMAL MUTATIONS
DELETIONloss of a piece of chromosome
EX. Cri du chat &Wolf-Hirschhorn syndrome
INVERSION AND TRANSLOCATIONInversion: chromosome breaks off and reattaches in reverse
Translocation: piece breaks off and attaches to another
* No problems in an individual since all genes are intact but there are problems with crossing over during meiosis
NONDISJUNCTION
failure of a chromosome to separate from its homologous chromosome
Trisomy - one too many chromosomes (2n=47)
EX: Down Syndrome, Kleinfelter’s Syndrome (XXY)
Monosomy - only one of a homologous pair (2n=45)
EX: Turner Syndrome (X)
KARYOTYPE: photo of chromosomes
GENE MUTATION A change in the genetic code of one gene Only one trait is affected
Point mutation: substitution, addition, or removal of a nucleotide
SUBSTITUTION results in new codon (could be different, same amino acid or stop)
EX. Sickle cell anemia
FRAME SHIFT MUTATION removal or addition of a nucleotide causes shift in entire sequence