Drosophila melanogaster is a species of fruit fly. Scientists have studied the inheritance patterns of many genetic traits in fruit flies. To carry out genetic crosses with fruit flies: - a specimen tube is prepared with food for the fruit flies, as shown in Fig. 1.2 - adult male and female fruit flies are added to the specimen tube to allow mating to take place - the specimen tube is kept in warm conditions for several days - the eggs laid by female fruit flies develop into pupae - adults are removed from the specimen tube before pupae mature into adult fruit flies - offspring emerge as adult flies $$\(10-15\)$$ days after eggs are laid. One of the genetic traits studied in fruit flies is eye colour．The normal（wild type）eye colour of D．melanogaster is red． Eye colour in D．melanogaster is controlled by several genes，including two genes that are located on separate chromosomes， $$\(\mathbf{A} / \mathbf{a}\)$$ and $$\(\mathbf{D} / \mathbf{d}\)$$ ． －Allele A is dominant to allele a． －Allele D is dominant to allele d． After crossing double heterozygotes (genotype AaDd), the student recorded the numbers of offspring in each of the four phenotypic groups. The student used a chi-squared ( $$\(\chi^{2}\)$$ ) test to analyse these data. The null hypothesis for this $$\(\chi^{2}\)$$ test was: There is no difference between the expected and observed numbers of offspring in each phenotypic group. The calculated value of $$\(\chi^{2}\)$$ was $$\(\mathbf{4 . 7 9 8}\)$$. The student compared 4.798 to the values in Table 1.2. Using Table 1.2 and the calculated value of $$\(\chi^{2}\)$$ of $$\(\mathbf{4 . 7 9 8}\)$$, state and explain what the student can conclude about the results. . . . . . .

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