Drosophila females heterozygous for each of three recessive autosomal mutations with independent phenotypic effects (thread antennae [th], hairy body [h], and scarlet eyes [st]) were testcrossed to males showing all three mutant phenotypes. The 1000 progeny of this testcross were:

hairy, thread 400

scarlet 398

wild type 57

hairy, thread, scarlet 53

thread, scarlet 45

hairy 44

thread 2

hairy, scarlet 1

(A)What is the genotype of the female Drosophila? Show the arrangement of alleles on the relevant chromosomes.

(B)Indicate the distance between each of the three genes. Show the calculations.

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.