Linkage Mapping Using Dihybrid Testcrosses in Fruit FliesIn fruit flies, the normal honey-gray body-color (bl*) is dominant to black (bl),having normal red eyes (pu+) is dominant to purple (pu), and having normalwings (vg+) is dominant to vestigial (vg). The three genes are located closetogether on the same chromosome.Your task is to use data from three dihybrid testcrosses to (1) calculaterecombination frequencies, (2) convert recombination frequencies into mapdistances, and (3) build a map of the chromosome interval covered by thethree genes, indicating their order and distances between them.BLACK PURPLE DIHYBRID CROSSIn the parental generation, you mate a pure-breeding wild-type female(bl+/blt;put/pu+) with a pure-breeding black, purple male (bl/bl;pu/pu) toproduce an F1 generation that is all wild-type (bl+/bl;pu*/pu). Note that the F1flies are all dihybrid.Next, you mate several F1 dihybrid females (bl+/bl;pu*/pu) with tester males,which are black, purple (bl/bl;pu/pu). The offspring of this dihybrid testcrossare:Phenotype Genotype Tester Gamete Dihybrid Gamete Number+/bl;+/pu444bl/blipu/pu443Wild-typeBlack, purplePurpleBlack34+/bl;pu/publ/bl;+/pu30bl publ publ publ pul++bl pu+ publ +The columns in blue (phenotypes and numbers of offspring) are what you cansee and count. Generally, only the mutant phenotypes are listed, so a fly withnormal body color and purple eyes is listed as purple in the table.The genotypes of the testcross offspring (orange) must be deduced from thephenotypes and knowing that the tester contributed bl pu gametes. Finally, youcan deduce the dihybrid gametes (green) by subtracting the tester gametecontribution from the offspring genotypes.Note that the two parental gamete types (+ + and bl pu) are the mostabundant, as expected. Use the data to calculate the recombination frequencyand the genetic map distance between the two genes. Record the mapdistance in your notes.

Name: Linkage Mapping Using Dihybrid Testcrosses in Fruit FliesIn fruit fli
Uploaded: 2024-03-20T06:42:55.000Z
Channel: Bartleby
Description: Linkage Mapping Using Dihybrid Testcrosses in Fruit FliesIn fruit flies, the normal honey-gray body-color (bl*) is dominant to black (bl),having normal red eyes (pu+) is dominant to purple (pu), and having normalwings (vg+) is dominant to vestigial