Mutation Definition change in organism resulting from change

Mutation Definition: change in organism resulting from change in gene structure CAUSES: 1. Errors in DNA replication: nucleotides lost, rearranged, paired wrong 2. Mutagen: internal or external factor causing mutation Chemical mutagens: dioxins, benzene, asbestos, DDT, cigarette smoke Radioactive Mutagens: UV rays, X-rays 3. Transposons: DNA sequence capable of randomly moving from one site to another in the genome 1

Gene Mutations Frameshift Mutations (English Sentence Analogy): Original: BIG DOG BIT TED Addition: BIG DOG BBI TTE D Deletion: IGD OGB ITT ED Substitution: BIG JOG BIT TED Point Mutations: Silent: DNA=ACA→ACG, m. RNA=UGU→UGC, AA=Cys →Cys Missense: DNA=ACA→ACC, m. RNA=UGU→UGG, AA= Cys→ Trp Nonsense: DNA=ACA→ACT, m. RNA=UGU→UGA, AA=Cys→STOP 2

Genetic Mutations Original Strand: Addition: Substitution: 3

Genetic Disorders Sickle Cell Anemia: - valine replaces glutamate in amino acid chain of hemoglobin - normal blood cells replaced by sickle shaped cells - abnormal cells block blood vessels, normal cells cannot get through, tissue starved of oxygen, nutrients Phenylketonuria (PKU): - tyrosine converted to phenylpyruvic acid - acid build up causes nervous system damage, mental retardation Albinism: - enzyme that converts tyrosine to melanin defective - subjects will have no skin/hair pigment, appear almost pure white 4

Chromosomal Mutations Inversion Duplication Translocation Deletion 5

Chromosomal Disorders Down's Syndrome: - extra chromosome #21 - facial features change (mongolism), mental processing slowed Turner's Syndrome: - absence of second X or Y chromosome - person is single X – short infertile female Kleinfelter's Syndrome: - 3 sex chromosomes – XXY - person is a male that grows tall with long limbs, generally have IQ’s significantly below siblings - sperm count may be reduced or person may be infertile 6