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Revisiting Mendel: Use of a behavioral assay to examine inheritance of traits in Drosophila Jeffrey M. Chalfant 1, Robin L. Cooper 2, Tawny Aguayo-Williams 1 Lexie Holtzclaw 3, Madison Loveless 3, Jennifer Wilson 3, and Doug Harrison 2 1 Dept. of STEM, Univ. of KY., Lexington, KY. 2 Dept of Biology, Univ. of KY., Lexington, KY. 3 Pulaski County High School, Somerset, KY |
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Using the established rules of Mendel and others, predicting the outcome of genetic crosses in model organisms is a common exercise for high school and college students. Frequently one uses phenotypic markers such as curly wings, eye color, and abnormal bristles. Yet many genetically-based traits, such as behavioral and physiological characteristics, are not observable as simple visible phenotypes. To demonstrate that such traits can likewise display Mendelian inheritance, we utilized an optogenetic system in Drosophila to modify response to light. We investigated the inheritance of behavioral responses associated with activating light-sensitive channelrhodopsin in body wall muscles. The frequency of responsive animals was examined over multiple generations beginning with two pure-breeding (homozygous) strains, each containing one of the two components needed to produce the light-sensitive proteins. The use of light-sensitive channels to examine the predicted genetic outcomes is an approach which can be used in teaching classical genetic principles using non-traditional phenotypes. This introduces concepts of transgenesis, genetically-modified organisms, and genetic contributions to behavior. The experiments can also introduce more complex genetic concepts, such as gene expression and cellular diversity, as well as physiological and behavioral traits of animals. This exercise is for advanced high school and college students.This module is presented in a variety of ways to be readily modified depending on equipment available in the classroom and the academic level of students. The modules were designed to be used in a hybrid or remote format with data provided or collected by in class participants. ABLE poster ABLE paper- draft |
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Resources: Papers and web links
Background reading in optogenetics and fly behaviors: Lights and Larvae: Using optogenetics to teach recombinant DNA and neurobiology. The Science Teacher 81 (#6):2-9. [PDF]. Optogenetics in the teaching laboratory: [PDF] Optogenetic manipulation of neural circuits and behavior in Drosophila larvae [PDF] Channelrhodopsin reveals experience-dependent influences on courtship [PDF] Selective neural activity in multiple freely moving Drosophila adults [PDF] Nature 2015- review on optogenetics [PDF] Nature 2015- review on optogenetics- commentary [PDF] Nature 2015- review on optogenetics- neuroscience [PDF] Optopharmacological tools for restoring visual function in degenerative retinal diseases (link to abstract) Top 10 discoveries in 10 years of optogenetics (link to) Ion channels with ChR channels (PDF) |
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Interesting side articles and links related to this topic http://www.sciencedaily.com/releases/ Anatomical and genotype-specific mechanosensory responses in Drosophila melanogaster larvae. Neuroscience Research 83:54-63 [PDF] |
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Table of which lines activate which type of neurons (PDF, MS Word ) Sample movies of larval behavior: Hot linked so click on title. Movies: Sample movies of larval behavior: (hot links with names-raw data files MP4) (21C for 24 hours 2nd instar to 3rd instar, No ATR feeding) Parentals
Chr2XXL-dish 1 Parentals
No
ATR-20C-Chr2 only no cross, 5 larvae dish 1 F1 (The
progeny of crossing virgin females of UAS-Chr2XXL with males of D42-GAL4.) - They all
freeze with Blue light 100% No
ATR D42 Chr2F1-dish 1 F2 (flies
that emerged from F1 were crossed to each other. The original parental
strains were removed) Without ATR one
slowed Chr2 for a lot-F2-dish 1 With ATR ATR
1 of 4- F2-dish1 ATR
1 of 4 -F2-dish 4 Movies: on YouTube: Parentals
Chr2XXL-dish 1 https://youtu.be/kscigOjvtk8
Parentals
No
ATR-20C-Chr2 only no cross, 5 larvae dish 1 https://youtu.be/GmyVFbbB9i0
F1 (The
progeny of crossing virgin females of UAS-Chr2XXL with males of D42-GAL4.) - They all
freeze with Blue light 100% F2 (flies
that emerged from F1 were crossed to each other. The original parental
strains were removed) (all non-ATR fed) one slowed
Chr2 for a lot-F2-dish 1 https://youtu.be/6K10bIqQrIo
With ATR ATR 1 of 4- F2-dish1
https://youtu.be/DwFSuFKZYpA
ATR 1 of 4 -F2-dish
4 https://youtu.be/QUXuslmGzvQ
Participants designing this content are : Jeffrey Chalfant, Department of STEM, College of Eductaion, University of Kentucky, Lexington, KY, jeffrey.chalfant@uky.edu Robin L. Cooper, 675 Rose St., Department of Biology, University of Kentucky, Lexington, KY 40506-0225 USA, RLCOOP1 at uky.edu Tawny Aguayo-Williams,West Jessamine High School, 2101 Wilmore Rd, Nicholasville, KY 40356, aguayowilliams at gmail.com Lexie Holtzclaw, Madison Loveless, and Jennifer Wilson at Pulaski County High School, Somerset, KY Doug Harrison, 675 Rose St., Department of Biology, University of Kentucky, Lexington, KY 40506-0225 USA, dough at uky.edu |
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website
maintained by Robin L. Cooper. Contact: RLCOOP1 at UKY.EDU |
