Ro_Lecture10

Ro_Lecture10 - Complementation The complementation test is...

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1 Complementation The complementation test is a rapid method of determining whether two independently isolated mutants with the same phenotype are in the same or different genes. Ornithine Citruline Arginine Enzyme1 Enzyme2 Both mutant1 and mutant2 cannot make arginine. If you are working with Neurospora, you can feed the intermediate (Citruline) to the mutants and see if they can now make arginine. Mutant1+ citruline=arginine Mutant2+citruline=mutant
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2 Eye Color mutants It is not often this easy. The wildtype eye color in flies is red Say you isolated two mutants in Drosophila that had white eyes Does that mean that both mutations reside in a single gene?
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3 Eye Color mutants It is not often this easy. The wildtype eye color in flies is red Say you isolated two mutants in Drosophila that had white eyes Does that mean that both mutations reside in a single gene? Precursor (white) Intermediate (white) Product (red pigment) Enzyme1 Enzyme2 Gene1 Gene2 Here is the pathway Mutations that disrupt either gene1 or gene2 give white eyes. Both genes are on the X-chromosomes. Lets say that mutations in two different genes give the white eye phenotype How do you determine if the two independently isolated white eye mutations are disrupting the same or different genes?
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4 White gene How do you determine if the two independently isolated white eye mutations are disrupting the same or different genes?
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5 White gene Mapping genes takes lots of crosses and is time consuming There is an easier way! *** To determine whether two independently isolated mutations are disrupting the same or different genes, the following cross is performed: yellow singed Shaven body forked white1 white2 You could map each mutation. If both mutations map to different regions of the X-chromosome then that would indicate that they are different genes. white1 x white2
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6 Naming mutations To describe a cross, we must first name the mutations The researcher who isolates the mutant names it!!!!! Cheapdate Cockeye king tubby Sevenless Bride of sevenless Daughter of sevenless The researcher who identified the first white eyed mutant (T.H. Morgan) named it white. Small case w designates the recessive mutant allele Upper case W designates normal (dominant) wildtype allele The researcher who identified the second mutant named it vanilla. Small case v designates recessive mutant allele Upper case V designates normal (dominant) wildtype allele Cross white1 ( ) x white2 ( ) white to vanilla w/w x v/Y White female Vanilla male
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The cross v Y w w What is the eye color of the w/Y males What is the eye-color of the w/v females? ? What are the genotypes and phenotypes of the cross
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This note was uploaded on 04/15/2008 for the course BIO 105 taught by Professor Sullivan during the Fall '08 term at UCSC.

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Ro_Lecture10 - Complementation The complementation test is...

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