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Genetic Disorders. How does a mutation affect the life of an organism? ESSENTIAL QUESTION: What are some options that scientists have to predict the possibility.

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Presentation on theme: "Genetic Disorders. How does a mutation affect the life of an organism? ESSENTIAL QUESTION: What are some options that scientists have to predict the possibility."— Presentation transcript:

1 Genetic Disorders

2 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?

3 Changes in the gene code _______________ that is made A change in the genetic code = ________________ mutation change the protein REVIEW

4 Many genetic ___________ result from changes in the DNA code so _________________ proteins are produced. DISORDERS NON-FUNCTIONING

5 Mutations that produce changes in a single gene = _________________ Mutations that produce changes in whole chromosomes = _____________________ KINDS OF MUTATIONS GENE MUTATIONS CHROMOSOMAL MUTATIONS

6 ____________________________: Change in the ______________ or ____________ of chromosomes CHROMOSOMAL MUTATIONS structure number Ex: Inversion of chromosome 12

7 Do you recognize this family? *Hint: They are from a TV show

8 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? SameDifferent 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.

9 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?

10 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 AA Normal 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?

11 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.

12 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.

13 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. AutosomalSex-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

14 Types of Genetic Diseases Sex-linked Autosomal recessive Autosomal dominance

15 Sex-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

16 What numbers do you See? Ex. Colorblindness X-linked disorder Most common in ? Males (1/10) Females (1/100)

17 AUTOSOMAL RECESSIVE DISORDER EXAMPLES: Phenylketonuria (PKU) Tay-Sachs Disease Cystic Fibrosis A mutation that causes a protein to be NON- FUNCTIONAL would appear _________ to the normal working allele. Recessive

18 Ex: Phenylketonuria (PKU) CAUSE: Mutation in gene for an ___________ that __________ an ___________ called phenylalanine Build up causes ________________________ MENTAL RETARDATION ENZYMEbreaks down amino acid X X The following is simply an example to assist with your understanding:

19 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 phenylalanine PREVENT ALLtested

20 Autosomal Dominant Disorders 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

21 Analyzing Karyotypes What can you tell by this karyotype?

22 Karyotype Organized profile of a human’s chromosomes Chromosomes are paired by centromere location banding pattern Size

23 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

24 EXPLANATION ACTIVITY Karyotyping Activity

25 Analyzing Karyotypes What can you tell by analyzing this karyotype?

26 Karyotype Analysis: Chromosomal Disorders Nondisjunction- 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

27 Find the chromosome that results from nondisjunction below That’s right, the sex chromosome has an extra Y. Trisomy, polysomy, or monosomy?

28 ELABORATION ACTIVITY Predict the genetic disorder by constructing a karyotype.


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