Transcript MUTATIONS
MUTATIONS Changes in DNA that affect genetic information What Causes Mutations? Mutations can be inherited. Parent to child Mutations can be acquired. Environmental damage Mistakes when DNA is copied Significance of Mutations • Some are harmful • Down Syndrome • Some are beneficial • Immunity to HIV • MOST ARE NEUTRAL! • Eye color • Birth marks Gene Mutations changes in one or more nucleotides on one section of DNA Example: Point, and Frameshift Point Mutations – changes in one or a few nucleotides THE FAT CAT ATE THE RAT 1 Nucleotide Substitution THE FAT HAT ATE THE RAT 3 nucleotide Insertion THE FAT CAT SAT ATE THE RAT 3 nucleotide Deletion THE FAT ATE THE RAT Gene Mutations Frameshift Mutations – shifts the reading frame of the genetic message so that the protein may not be able to perform its function. THE FAT CAT ATE THE RAT 1 nucleotide Insertion THE FAT HCA TAT ETH ERA T 1 nucleotide Deletion TEF ATC ATA TET HER AT Chromosome Mutations Changes in number and structure of entire chromosomes Original Chromosome Deletion Duplication Inversion Translocation ABC * DEF AC * DEF ABBC * DEF AED * CBF ABC * JKL GHI * DEF Karyotype Set of chromosome photographs grouped in order and in pairs Can be used to diagnose chromosomal mutations Chromosome Mutations Down’s Syndrome Chromosome 21 does not separate correctly. They have 47 chromosomes in stead of 46. Children with Down’s Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of inteligence. Chromosome Mutations Cri-du-chat Deletion of material on 5th chromosome Characterized by the cat-like cry made by cri-du-chat babies Varied levels of mental handicaps Pataos Syndrome Trisomy 13 Incomplete brain Severe mental retardation Cleft lip and palate Absence of eyes Heart valve disorder Average live expectancy = 130 days Edward’s Syndrome Trisomy 18 Clenched fists Rocker bottom feet Malformed heart 3 months – 15 years Sex Chromosome Abnormalities Klinefelter’s Syndrome (Hermaphrodite) XXY, XXYY, XXXY Male Sterility Small testicles Breast enlargement Sex Chromosome Abnormalities Jacob’s Syndrome XYY Normal male traits Often tall and thin Associated with antisocial and behavioral problems Sex Chromosome Mutations Turner’s Syndrome X Female sex organs don't mature at adolescence sterility short stature Sex Chromosome Mutations Trisomy X Female Little or no visible differences tall stature learning disabilities limited fertility http://www.angelfire.com/ca2/BornHermaphrodite/ Some mutations even make it on SNL!