Genetic Genetic DisordersDisorders
How does a mutation affect the life of an organism?
ESSENTIAL QUESTION:
What are some options that scientists have to predict the possibility of genetic diseases
in infants?
Do all mutations cause a change in the physical
appearance of an organism?
Changes in the gene code _______________ that is made
A change in the genetic code =________________
mutation
change the protein
REVIEW
Many genetic ___________ result fromchanges in the DNA
code so _________________
proteins are produced.
DISORDERS
NON-FUNCTIONING
Mutations that produce changes in a single gene = _________________
Mutations that produce changes in whole chromosomes = _____________________
KINDS OF MUTATIONS
GENE MUTATIONS
CHROMOSOMAL MUTATIONS
____________________________:Change in the ______________ or
____________ of chromosomes
CHROMOSOMAL MUTATIONS
structure
number
Ex:Inversion of chromosom
e 12
Do you recognize this family?*Hint: They are from a TV show
They are the Roloff family from TLC’s show Little People Big World
How are the members of this family the same?
How are they different?
Same Different
facial features, hair color
etc.
height
Some family members (including the parents) exhibit the characteristic short stature
of Achondroplasia, a dominant genetic disorder that results in a form of dwarfism.
EXPLORATION ACTIVTIY:How is it possible for Matt and Amy (the parents) to have a child like Zach with
Achondroplasia, dominant genetic
disorder, and three children who do not have the disease?
THAT’S RIGHT!!!Matt and Amy both have an
Aa genotype. This would allow them to have children
who exhibit dwarfism as well as children of normal
height.Dwarfism: Aa or AANormal height: aa
DID YOU QUICKLY THINK, Since some of the Roloff children do not exhibit dwarfism, what do we know about Matt and Amy’s genes for Achondroplasia?
DID YOU KNOW?
1. As the occurrence of infectious and nutritional diseases decreases in developed countries, genetic diseases have come to the forefront.
2. At least one-third of the children in pediatric hospitals are there because of hereditary disorders.
3. Chromosomal mutations account for about half of all first-trimester miscarriages.
4. A total of about 7% of the population suffers from some type of genetic disorder.
Examples:-changes that cause deformities (cleft lip)-metabolic change (phenylketonuria “pku”)-structural changes (albinisim)
GENETIC DISEASES: inherited disorders reflecting gene mutations or abnormalities in chromosome structure or number, which result in a functional or anatomical change.
How are genetic disorders
transmitted or inherited? Genetic diseases can be inherited in a manner similar to that of normal traits. These diseases include single-gene
disorders that are autosomal or sex-linked.
Autosomal Sex-linked
means that the gene is present in a
chromosome pair other than the sex
chromosomes
means that the gene is located on a sex
chromosome
Types of Genetic Types of Genetic DiseasesDiseasesSex-linked
Autosomal recessiveAutosomal dominance
Sex-Linked GenesSex-Linked Genes
Pattern of inheritance is located on the X-chromosome or the Y- chromosome
Y is much smaller
Therefore, there are more X-linked disorders/traits
What numbers do you What numbers do you See?See?
Ex. Colorblindness
X-linked disorder
Most common in ?
Males (1/10)
Females (1/100)
AUTOSOMAL RECESSIVEDISORDER
• EXAMPLES:
• Phenylketonuria (PKU)
• Tay-Sachs Disease
• Cystic Fibrosis
A mutation that causes a protein to be A mutation that causes a protein to be NON-FUNCTIONAL would appear _________ NON-FUNCTIONAL would appear _________
to the normal working allele.to the normal working allele.RecessiveRecessive
Ex: Phenylketonuria (PKU)
CAUSE: Mutation in gene for an ___________ that __________ an ___________ called phenylalanine
Build up causes ________________________MENTAL RETARDATION
ENZYME breaks downamino acid
X
X
The following is simply an example to assist with your understanding:
Phenylketonuria (PKU)
____ babies are ________for PKU before they leave the hospital.
Treatment: Need a diet _____________________ to extend life and ______________ mental retardation
If phenylalanine is an _____________, what type of foods should PKU patients avoid? __________________
amino acid
PROTEINS !
LOW in phenylalaninePREVENT
ALL tested
Autosomal DominantDisorders
• A mutation that codes for a new protein whose action masks the normal allele appears as a _____________ mutation. HENCE,
• _________________________ GENETIC DISORDERS:
• Examples:
• Huntington’s Disease
• Achondroplasia (Roloff family )
DOMINANT
dominant
Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by this karyotype?
KaryotypeKaryotypeOrganized profile of a human’s chromosomes
Chromosomes are paired by
centromere location
banding pattern
Size
REVIEW
Chromosomes that determine the sex of an organism = _________________
All other chromosomes = _________________
Sex chromosomes
autosomes
Humans have two sex chromosomes
and _____ autosomes
X Y
44
EXPLANATIONEXPLANATIONACTIVITYACTIVITY
• Karyotyping Activity
Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by analyzing this karyotype?
Karyotype Analysis: Karyotype Analysis: Chromosomal Chromosomal
DisordersDisordersNondisjunction- occurs when either homologous chromosome fails to separate during meiosis
Results abnormal # of chromosomes in gametes
Trisomy = 1 extra homologous chromosome (3)
Polysomy = more than 1 extra
Monosomy = only 1 chromosome
Examples: Down syndrome, Klinefelter syndrome, Turner Syndrome
Find the chromosome that results from nondisjunction below
That’s right, the sex chromosome has an extra Y.
Trisomy, polysomy, or monosomy?
ELABORATIONACTIVITY
• Predict the genetic disorder by constructing a karyotype.
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