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.