Chapter 14, Problem 8b
In garden peas, yellow seeds (Y) are dominant to green seeds (y), and inflated pods (I) are dominant to constricted pods (i). Suppose you have crossed YYII parents with yyii parents. List the genotype(s) of gametes produced by F1 individuals.
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A plant with orange, spotted flowers was grown in the greenhouse from a seed collected in the wild. The plant was self-pollinated and gave rise to the following progeny: 88 orange with spots, 34 yellow with spots, 32 orange with no spots, and 8 yellow with no spots. What can you conclude about the dominance relationships of the alleles responsible for the spotted and unspotted phenotypes? What can you conclude about the genotype of the original plant that had orange, spotted flowers?
In peas, purple flowers are dominant to white. If a purple-flowered, heterozygous plant were crossed with a white-flowered plant, what is the expected ratio of genotypes and phenotypes among the F1 offspring? If two of the purple-flowered F1 offspring were randomly selected and crossed, what is the expected ratio of genotypes and phenotypes among the F2 offspring?
In garden peas, yellow seeds (Y) are dominant to green seeds (y), and inflated pods (I) are dominant to constricted pods (i). Suppose you have crossed YYII parents with yyii parents. Draw the F1 Punnett square and predict the expected F1 phenotype(s).
In garden peas, yellow seeds (Y) are dominant to green seeds (y), and inflated pods (I) are dominant to constricted pods (i). Suppose you have crossed YYII parents with yyii parents. Draw the F2 Punnett square. Based on this Punnett square, predict the expected phenotype(s) in the F2 generation and the expected frequency of each phenotype.
In parakeets, two autosomal genes that are located on different chromosomes control the production of feather pigment. Gene B codes for an enzyme that is required for the synthesis of a blue pigment, and gene Y codes for an enzyme required for the synthesis of a yellow pigment. Green results from a mixture of yellow and blue pigments, and recessive mutations that prevent production of either pigment are known for both genes. Suppose that a breeder has two green parakeets and mates them. The offspring are green, blue, yellow, and albino (unpigmented). Based on this observation, what are the genotypes of the green parents? What genotypes produce each color in the offspring? What fraction of the progeny should exhibit each type of color?
Imagine repeating the experiment on epigenetic inheritance that is shown in Figure 19.6. You measure the amount of radioactive uridine (U) incorporated into Hnf4a mRNA in counts per minute (cpm) to determine the level of Hnf4a gene transcription in rats born to mothers fed either a normal diet or a low-protein diet. The results are 11,478 cpm for the normal diet and 7368 cpm for the low-protein diet. For this problem, your task is to prepare a graph similar to the one at the bottom of Figure 19.6 that shows the normalized results for the low-protein diet relative to the normal diet. Normalizing values means that the value obtained from one condition is expressed as 1.0 (the norm; the normal diet in this case) and the values obtained from any other conditions (low-protein diet in this case) are expressed as decimal values relative to the norm.