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A TIDBIT by: Pat, Tammy, Marcie, Debbie, Eric and Tingting Stamped DNA How ‘imprinting’ affects inheritance.

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Presentation on theme: "A TIDBIT by: Pat, Tammy, Marcie, Debbie, Eric and Tingting Stamped DNA How ‘imprinting’ affects inheritance."— Presentation transcript:

1 A TIDBIT by: Pat, Tammy, Marcie, Debbie, Eric and Tingting Stamped DNA How ‘imprinting’ affects inheritance

2 Group 2: Heredity Teachable Unit: Epigenetics Context Class: sophomore level genetics class ~ students Previous concepts: Mendelian inheritance, DNA structure, intro molecular genetics Reading assignment for class: Text information on epigenetics This is the first lesson in the unit, but it will be followed by two lessons on mechanism and other epigenetic phenomena. Since this topic has more challenging content, we have chosen to use guided active learning to help students construct a knowledge base, followed by more challenging homework assignments. The unit will have 2 additional lessons or tidbits.

3 Misconceptions  All inheritance is based on DNA nucleotide sequence.  All human genes are equally expressed from both alleles.  All genetic diseases are caused by a point mutation.  The active genome of males and females is the same.

4 Unit Learning Goals and Flow of Content Students will understand:  The concepts of epigenetics.  Overview and definitions  Contrast with Mendelian Inheritance  The molecular basis of different types of epigenetic phenomena.  Imprinting: Normal and Disease states  Histone Modification  RNA interference  Prions  That epigenetics contributes to both diversity and disease.  Environmental impacts on the epigenome  Epigenetic determinants of cancer

5 Prader-Willi Angelman These two very different syndromes are caused by the same deletion

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7 Learning Outcomes for Today  Students will define imprinting.  Contrast imprinting and Mendelian inheritance.  Predict an outcome from a genetic cross involving non-Mendelian inheritance.

8 What is Imprinting?  Imprinted chromosomes are “marked”  Imprinting differs in sperm and egg  Imprinting turns off specific genes  Imprinting does not change the nucleotide sequence CH 3

9 Think-Pair-Share/ review from last semester Hypothesize some ways that the DNA is imprinted? Formative Assessment; Bloom’s Synthesis (3/4)

10 DNA can be Methylated on cytosine residues Gene expression active Gene expression inactive -CH 3 (METHYL group)

11 Gene A Paternal Gene A Maternal X CH 3 X MendelianImprinted A mutation in Gene A may cause a change in phenotype when: DominantRecessiveMaternally imprinted Paternally imprinted 1. The maternal copy is mutated 2. The paternal copy is mutated 3. When both copies are mutated With your clicker, press A for “yes” and B for “no” Yes No Yes No Yes No Yes Formative Assessment; Recall; Bloom’s 1 Formative Assessment; Analyze; Bloom’s 3/4 Mutation

12 Optional activity  A 1-minute essay could be included here to summarize knowledge of the previous table. Perhaps, “Summarize the key difference between Mendelian inheritance and inheritance of imprinted genes.”  Space is included on the handout chart for this question.

13 CLICKER: Based on the figure below, which proteins are normally produced? Click A for protein A B for protein B C for BOTH D for NEITHER ANSWER = BOTH A B

14 CLICKER: Which proteins are produced with maternal deletion? Click A for protein A B for protein B C for BOTH D for NEITHER ANSWER = only protein A is made A

15 CLICKER: Which proteins are produced with paternal deletion? Click A for protein A B for protein B C for BOTH D for NEITHER ANSWER = only protein B is made B

16 Gene A Maternal X CH 3 Gene B Gene A Maternal X CH 3 Gene B Normal Paternal deletion Maternal deletion Gene A Paternal Gene B X CH 3 Paternal Gene A Paternal Gene B X CH 3 Maternal [ ] [ ] A A B B

17 Prader-Willi Angelman These two very different syndromes are caused by the same deletion

18 Compose a 1 minute essay that explains the basis for the difference between Prader-Willi and Angelman. Formative assessment; Bloom’s level Analysis 3

19 Homework: To further assess your understanding of Mendelian inheritance versus inheritance of imprinted genes Is this disease dominant? Why or why not? Is this disease recessive? Why or why not? Can the disease be inherited from the paternal side? Can the disease be inherited from the maternal side? Does this show Mendelian inheritance? 1.Define imprinting in your own words. 2.Look at the following pedigree and answer the questions below.

20 Entrance Ticket: Parthenogenesis (“Virgin Birth”)  Parthenogenesis is the ability of some species to produce offspring without any male involvement  Parthenogenesis is observed in various animal species, but not mammals How could imprinting prevent parthenogenesis? Formative Assessment; Bloom’s Analyze, 4

21 SCIENTIFIC TEACHING  Active Learning Clicker Brainstorming (think-pair- share) Group problem solving Entrance ticket Call-out  Assessment-all of above formative Individual take-home questions are summative  Diversity Auditory/visual Social learning and individual work GoalsActive Learning/Assessment Bloom’s Level/Verb Define Epigenetics and Imprinting Think/Pair/ Share Brainstorming Summative: Homework/write in your own words Hypothesize/grapple with/3-4 Define/1 Contrast imprinting and Mendelian inheritance. Worksheet activity/ individual/Peer interaction/Group problem solving/call out/clicker assessment Recall/1 Analyze/3-4 Predict an outcome from a genetic cross involving non-Mendalian inheritance. Formative/visual/clicker questions 1 minute essay Summative:Homework/ Pedigree/Parthenogenesis Predict/ 3 Compose/Explain/Analyze /3 Analyze/Predict/relate/3-4


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