We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
supports HTML5 video
Published byMorgan Poole
Modified over 4 years ago
Chapter 14 Sec 1: Genes in Action
Mutation: The Basis of Genetic ChangeThe change in the structure or amount of the genetic material of an organism
Mutant An individual whose DNA or chromosomes differ from a previous or normal state.
Evolution Genetic differences among organisms originate as some kind of genetic mutation
Causes of Mutation Occur naturally as accidental changes to DNA or to chromosomes during the cell cycle Mutagens: environmental factors like radiation & some chemicals
Effects of Mutation A small change in the DNA can affect one amino acid in a protein Only noticed if they cause a disease
Kinds of Mutations Different kinds of mutations are recognized as either changes in DNA or changes in the results of genes
Mutations as Changes in DNA
Point Mutation Change of a single nucleotide in a sequence from one kind of base to another
Insertion or Deletion Errors in replication can cause the deletion or insertion of a nucleotide
Mutations as Changes in Results of Genes
Silent Mutation It has no effect on a gene’s function Point mutation
Missense Mutation Results when a codon is changed such that the new codon codes for a different amino acid
Frameshift Mutation Causes the starting point of “reading” the gene to change which translates to different codons
Nonsense Mutation Results when a codon is changed to a STOP signalProtein may fail to function
More or Fewer Amino AcidsIf the insertion or deletion is a multiple of 3, reading will be preserved Protein will have fewer amino acids
At a chromosome level In eukaryotic cells, the process of meiosis creates the chance of mutations at the chromosome level
Deletion Occurs when a piece of chromosome is lost
Duplication Occurs when a piece remains attached to its homologous chromosome after meiosis
Inversion Occurs when a piece reattaches to its original chromosome, but in a reverse direction
Translocation Occurs when a chromosome piece ends up in a completely different, nonhomologous chromosome
Gene Rearrangement Chromosomal mutation can move an entire gene to a new location Likely to disrupt the gene’s function
Effects of Genetic Change
Germ Cell Mutations in germ cells can be passed on to the next generation
Sickle Cell Anemia Recessive traitPoor blood circulation, pain, organ damage
Tay-Sachs Disease Recessive traitDeterioration of central nervous system Death in early childhood Caused by defective form of an enzyme
Cystic Fibrosis Recessive trait Mucus buildup in organsDifficulty breathing and digesting
Hemophilia Recessive, sex linkedFailure of blood to clot, excessive bleeding and bruising
Romanoffs - Hemophilia
Pedigree for Hemophilia
Huntington Disease Dominant traitGradual deterioration of brain tissue in middle age Shorter life expectancy
Achondroplasia Homozygous Dominant – Don’t surviveHeterozygous Dominant – Lead normal lives and can reproduce
Camptodactyly Genetic abnormality that affects the shape and movement of fingers Variation in the phenotype of the trait
Cri-du-chat Deletion from chromosome 5 resulting in mental retardation and the development of an abnormally shaped larynx
Progeria Syndrome A set of symptoms that characterize a disorderHutchinson-Gilford Progeria syndrome: mutated gene that leads to premature aging and reduced life expectancy
Progeria Syndrome Gene mutates at randomDominant over its normal partner on the homologous chromosome
Large-scale genetic changeCan occur by misplacement, recombination, or multiplication of entire chromosomes
Nondisjunction When pairs of chromosomes fail to separate properly
Down Syndrome Extra chromosome 21 Mental retardationCongenital heart defects Shorter limbs
Turner Syndrome (XO) Missing one X chromosomeFemale in appearance but their sex organs do not develop at puberty and they are sterile Short stature, broad based neck
Klinefelters Syndrome (XXY)Male in appearance and sterile Taller than average Usually notice when males don’t develop at puberty
XYY Individuals are somewhat taller than average and often have below normal intelligence Used to think they were prone to violence
Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring, only to descendant cells)
KARYOTYPE AND GENETIC DISORDERS
Chromosomes and Inheritance
Genetic Changes Any mistake or change in the DNA sequence is called a mutation. Types of mutations are: point mutation frameshift mutation chromosomal.
What’s a “mutagen”? What does a mutation do to DNA? If a mutation affects a gene, then what might happen to the protein sequence?
Pedigrees, Mutations and Karyotypes
Genetic Diseases Autosomal Recessive Diseases – PKU (phenylketonuria) caused by a recessive allele found on Chromosome 12 Causes accumulation of phenylalanine.
Section 1: Mutation and Genetic Change
Unit 4 Part 1. DNA cannot leave the nucleus. Through transcription an mRNA copy of DNA is made. RNA Polymerase unwinds and unzips the DNA. RNA.
GENETIC DISORDERS. ____________________________ –change in a gene resulting in change in genetic information may be spontaneous or caused by a mutagen.
Human Genetics Chapter 14 in the Textbook.
Chromosomes and Human Inheritance Diploid = 46, Haploid = 23 Sex chromosomes different than others Not homologous pairs Female = two X chromosomes.
Mutations and other genetic issues
Complex Inheritance and Human Heredity
CHAPTER 14: Genes in Action
Review for Genetics Test
© 2020 SlidePlayer.com Inc. All rights reserved.