PROJECT - Mapping an unknown Drosophila gene
The aim of this exercise is to allow you the freedom to map a Drosophila gene in your own time and using your initiative. You are assigned an autosomal recessive mutation to map to its two closest markers based on provided dihybrid test cross data. Only map your gene with respect to the other autosomal genes shown in Table 1. Note that you cannot analyse the results of crosses between two different genes that affect the same body part as these genes will interact.
Scenario: You are an honours student and your project is to characterise a homozygous recessive mutant strain of Drosophila. A previous student has generated dihybrid testcross data for 10 other autosomal recessive genes from Drosophila and this data is available to you (on Moodle) to map your assigned gene to its two closest markers. Work with the provided data and then compare your findings with published recombination distances to determine the accuracy of your map. Discuss if the data that has been provided to you is sufficient to produce an accurate map in comparison to published data, and suggest future improvements that will make your map more accurate. Also discuss both the function of your assigned gene and the broader utility of gene mapping, for example for human disease genes.
Table 1: Recessive mutations in FlyLab and the body part they affect
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Body colour
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Eye colour
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Bristles
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Wing size
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Wing shape
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Wing vein
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Black
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Brown
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Forked
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Apterous
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Dumpy
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Crossveinless
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Ebony
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Purple
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Singed
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Miniature
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Scalloped
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Radius Incompletus*
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Sable
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Sepia
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Spineless
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Vestigial
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|
|
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Tan
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White
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|
|
|
|
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Yellow
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|
|
|
|
|
*This mutation was later renamed Knirps - the gene is now known as this
Report structure (word limits are a guide only).
Abstract (word limit 150 words) - Abstracts provide a summary of the project. They should start with some brief background information (this should include a sentence giving a broad introduction to the field, then a sentence of more detailed background relevant to your study). This should be followed by the results, and then the main conclusions.
Introduction (word limit 500 words) - This should introduce and explain the concepts behind genetic mapping and how maps are made. Do not copy the lecture notes or the prac manual or cite these. Cite where appropriate (eg, general reviews).
Aims - This should be brief and specific.
Results - Include here the mapping results for the two closest genes to your assigned gene and a comparison with published data on map distances that you have found.
Discussion (word limit 1000 words) - Briefly summarise the results that you obtained and discuss any discrepancies that you see between your data and published sources on map distances. Discuss how the experimental approach could be improved if given an opportunity to set up your own crosses and generate your own data.
Include in your discussion the function of the gene that you have been assigned. Comment more widely on the importance and significance of gene mapping.
References - Only list the references that you cite in the text. Please use the CSIRO referencing style. The CSIRO citing and referencing guide is available on Moodle.
Appendix - Present here additional cross data not included in the main results section (with justification) making sure that the main report refers to the appendix.
Attachment:- Assignment Files.rar