Wild type Drosophlia melangaster have normal wings and red eyes any unknown vial of different looking fruit flies is found. These flies are pure-breeding for scarlet eye color and dumpy wings. To investigate the genetic basis of the differences of the difference between wild type and the unknown flies, reciprical crosses were formed. The progeny of a cross between a wild type male and a virgin unknown female produced progeny that were all like wild type. The progeny of a cross between an unknown male and a virgin wild type female gave the same result. The F1 were allowed to mate to produce an F2 population that consisted of 85 flies like wild type, 35 with red eyes and dumpy wings, 25 with scarlet eyes and normal wings, and 15 with scarlet eyes and dumpy wings. Use the information to answer these questions below.
1. The convention for naming genes is to name them after the phenotype seen in the mutant fly. Based on this convention, which of the following is the best choice for naming the gene involved in fly eye color that was identified in this study of flies (choices are white, red, normal, dumpy, or scarlet)
2. The wild type allele of fly genes are designated with a superscript + (plus) and recessive mutant alleles are designated with a superscript - (minus). Using the naming convention in the previous question, two genes were identified: scarlet (st) and dumpy (dp). Based on the naming convention and the use of +/- superscripts, which of the following is the best description of the F1 flies in this problem? (choices are st+st+dp+dp+, st-st-dp+dp+, st+st-dp+dp-, st-st-dp-dp-, or st+st-dp+dp+)
3. One hypothesis that explains the distribution of phenotypes among F2 progeny is that, during gamete formation, the alleles of each gene segregate and the alleles of st and dp assort independently. Based on this hypothesis, which of the following is the best choice for the expected distribution of phenotypes among the F2?
(choices are One hypothesis that explains the distribution of phenotypes among F2 progeny is that, during gamete formation, the alleles of each gene segregate and the alleles of st and dp assort independently. Based on this hypothesis, which of the following is the best choice for the expected distribution of phenotypes among the F2?
- 90 like wild type; 30 red-eyed, normal wings; 30 red-eyed, dumpy wings; 10 scarlet-eyed, normal wings.
- 90 like wild type; 30 red-eyed, dumpy wings; 30 scarlet-eyed, normal wings; 10 scarlet-eyed, dumpy wings.
- 90 scarlet-eyed, dumpy wings; 30 red-eyed, dumpy wings; 30 scarlet-eyed, normal wings; 10 like wild type
- 90 like wild type; 30 scarlet-eyed, dumpy wings; 30 scarlet-eyed, normal wings; 10 red-eyed, dumpy wings.
4. The actual numbers of flies that were identified in each of the four phenotypic categories differed from the numbers predicted by the hypothesis of segregation and independent assortment. The chi-square test is a way to determine whether the observed results differ significantly from expected. Which of the following is the best choice for the P-value from a chi-square test of the observed and expected results in this problem (calculate the chi-square and P-values using the four phenotypes listed in the orgininal problem)?(choices are)
- P < 0.05
- 0.05 ≤ P < 0.10
- 0.10 ≤ P < 0.20
- 0.20 ≤ P < 0.30
- 0.30 ≤ P < 0.40
- 0.40 ≤ P < 0.50
5. If thePvalue derived from a chi-square test was 0.01 (it was not in this problem!), which of the following statements is the best interpretation? (choices are)
- Results that differ this much from expected will occur only 1 % of the time if the hypothesis is correct.
- Results that differ this much from expected will occur 99 % of the time if the hypothesis is correct.
- The hypothesis correct.
- The hypothesis is incorrect.