Workshop 2: dihybrid crosses
For each of the crosses listed below:
(1) mate the parent flies
(2) note down the F1 phenotypes and numbers
(3) mate the female F1 to the male F1 (provided there is only one female and one male phenotype)
(4) note down the F2 phenotypes and numbers
Then:
(1) determine (hypothesise) the mode of inheritance of each mutation (autosomal, sex-linked, dominant, recessive and combinations thereof) and predict the phenotype ratios in the F2
(2) outline the segregation of alleles and phenotypes from parents to F2
(3) predict what the phenotypic segregation ratios should be in the F1 and F2
(4) do a chi-square test of your hypothesis on the F2 data
(5) accept or reject your hypothesis
(6) explain your reasoning
The crosses are:
black body female x eyeless male
shaven bristles female x lobe eyes male
white eyes female x vestigial wing male
lobe eyes female x crossveinless wing male
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