Gene mapping problem-answer

Gene mapping - of genes number of recombinants RF = X 100 total progeny The recombination frequency is used directly as an estimate map units(mu RF

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Gene mapping problem The following data are from Bridges and Morgan' work on recombination between the genes black (black body color), curved (curves wings), purple (purple eyes), speck black specks on wings), and vestigial (crumpled wings) in chromosome 2 of Drosophila : Genes in cross Total progeny Number of recombinants black, curved 62679 14237 black, purple 48931 3026 black, speck 685 326 black vestigial 20153 3578 curved, purple 51136 10205 curved, speck 10042 3037 curved, vestigial 1720 141 purple, speck 11985 5474 purple, vestigial 13601 1609 speck, vestigial 2054 738 On the basis of the data, map the chromosome for these five genes as accurately as possible. (Remember that determinations for short distances are more accurate than those for long ones.)
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Solving the problem First, the recombination frequency (RF) has to be calculated for each set
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Unformatted text preview: of genes: number of recombinants RF = ---------------------------------------- X 100 total progeny The recombination frequency is used directly as an estimate map units (mu) RF for black, curved = (14237/62679) X 100 = 22.7% or 22.7 mu RF for black, purple = 6.1 mu RF for black, speck = 47.6 mu RF for black vestigial = 17.7 mu RF for curved, purple = 19.9 mu RF for curved, speck = 30.2 mu RF for curved, vestigial = 8.2 mu RF for purple, speck = 45.6 mu RF for purple, vestigial = 11.8 mu RF for speck, vestigial = 35.9 mu To draw the map start with the black gene and the lowest map unit value. The gene following the black one on the chromosome is purple (6.1 mu between them). The next one is vestigial (17.7 mu) and so forth. 6.1mu 11.8 mu 8.2 mu 30.2 mu black purple vestigial curved speck...
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This note was uploaded on 06/09/2011 for the course BIOLOGY 2c03 taught by Professor Dej during the Spring '11 term at McMaster University.

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Gene mapping - of genes number of recombinants RF = X 100 total progeny The recombination frequency is used directly as an estimate map units(mu RF

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