Transcript Gene Mutations - Lyndhurst School

Genetic Mutations
What Are Mutations?
 Changes in the nucleotide sequence of
DNA
 May occur in body cells and are not
passed to offspring
 May occur in gametes (eggs & sperm)
and be passed to offspring
Are Mutations Helpful or
Harmful?
 Mutations happen regularly and often
neutral
 Many mutations are naturally repaired
by enzymes
 Causes of mutations:
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Natural
Chemicals
Radiation
Other environmental factors
Are Mutations Helpful or
Harmful?
 Some mutations are harmful and can
cause:
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Cancer
Birth defects
Physical impairments
Other life altering conditions
 Some mutations may improve an
organism’s survival
 This is know as evolution
Chromosome Mutations and Gene Mutations
Chromosome Mutations
 May Involve:
 Changing the
structure of a
chromosome
 The loss or
gain of part of
a chromosome
Types of Chromosome
Mutations
 Five types exist:
 Deletion
 Inversion
 Translocation
 Nondisjunction
 Duplication
Deletion
Due to breakage, a
piece of a
chromosome is lost
Inversion
Chromosome segment breaks off
Segment flips around backwards
Segment reattaches
Duplication
Occurs when
a gene
sequence is
repeated
Translocation
Involves two
chromosomes
that not
homologous
Part of one
chromosome is
transferred to
another
chromosomes
Nondisjunction
 Caused by a failure of chromosomes to
separate during meiosis
 As a result, the gamete will have too many
or too few chromosomes
Gene Mutations
What are
Gene
Mutations?
Change in the nucleotide
sequence of a gene
May only involve a single
nucleotide
May be due to copying
errors, chemicals, viruses,
etc.
Types of Gene Mutations
 Include:
 Point Mutations
 Substitutions
 Insertions
 Deletions
 Frameshift
Point Mutation
What is it?
 Change of a single
nucleotide
 Includes the
deletion, insertion,
or substitution of
ONE nucleotide in
a gene
Example:
 Sickle Cell
disease is the
result of one
nucleotide
substitution
 Occurs in the
hemoglobin gene
Frameshift Mutation
 Inserting or
deleting one or
more nucleotides
 Changes the
“reading frame”
like changing a
sentence
 Causes proteins to
be built incorrectly
Food inc
Class Discussion
Discussion
 See teacher for details
Modern Genetics
Objectives
 Describe ways of producing organisms with desired
traits
 State the goal of the human genome project
Selective Breeding
 Definition: The process of selecting organisms with
desired traits to be the parents of the next
generation
 This process has been used for hundreds of years
 Two Types:
 Inbreeding- crossing two individuals that have similar
characteristics
 Hybridization- crossing two genetically different
individuals
Cloning
 Cloning- a technique used to produce offspring with
desired traits (identical to the traits of another
organism)
 Clone- an organism that has identical gene as the
one from which it was produced
 WATCH - BrainPop: Dolly the Sheep
Genetic Engineering
 Genetic engineering- genes from one organism are
transferred into the DNA of another
 Examples ….
 Gene therapy- use of genetic engineering to correct
genetic disorders.
 Concerns…
The Human Genome
Project
 Genome- all of the DNA in one cell of an organism
 Goal of the Human Genome Project:
 Identify the sequence of every gene in the human genome
 Interesting Facts:
 The DNA of humans consists of at least 30,000 genes
 Each gene has about 3,000 bases (A, T, G, C)
 Other Uses:
 DNA Fingerprinting
 Technology used in the Human Genome Project can be
used to identify people and show whether people are
related