Concept explainers
Red eyes is the wild-type
Cross 1: Males with vermilion
354 offspring, all with red eyes
Cross 2: Males with
212 male offspring with vermilion eyes
221 female offspring with red eyes
Explain the pattern of inheritance based on these results. What additional crosses might you make to confirm your hypothesis?
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Genetics: Analysis and Principles
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- In the pearl-millet plant, color is determined by three alleles at a single locus: Rp1 (red), Rp2 (purple), and rp (green). Red is dominant over purple and green, and purple is dominant over green (Rp1 > Rp2 > rp). Give the expected phenotypes and ratios of offspring produced by the following crosses. a. Rp1/ Rp2 × Rp1/ rp b. Rp1/ rp × Rp2/ rp c. Rp1/ Rp2 × Rp1/ Rp2 d. Rp2/ rp × rp/ rp e. rp/ rp × Rp1/ Rp2arrow_forwardTwo pure-breeding strains of flies are mated, and the F1 are intercrossed. The first strain has curled wings and black bodies. The second strain has straight wings and brown bodies. The F2 progeny are 271 straight wings with brown bodies, 31 curled wings with black bodies, 94 curled wings with brown bodies and 90 straight wings with black bodies. If instead of the above, assume the wing shape gene and the body color gene are completely linked. From parents that are curled winged with brown bodies mated to straight winged with black bodies, what would be the outcome of an F1 intercross? (Specify the phenotypes and the frequency of each expected).arrow_forwardA particular walnut rooster was crossed to a pea hen, and the progeny consisted of 12 walnut, 11 pea, 3 rose, and 4 single chickens. What are the likely genotypes of the parents?arrow_forward
- The tiny blue-eyed Mary flower is often one of the first flowers seen in the spring in some regions of the United States. The flower is normally blue, but sometimes a white or pink flower variation is found. The following data were obtained after several crosses. A student claims that these flower colors are an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and white cross can best be explained by epistasis, where another gene product influences phenotype expression. This data supports this claim because in order to produce a __________ (pink, white, or blue) flower, a gene for a switch that 'turns on' the color gene would be recessive, meaning it has a mutation that causes it to be 'off'. In order to express a color, this switch needs to be in the dominant form. The color gene is a structural gene that has two variants: a dominant trait, ______ (pink, white, or blue) and a recessive _______ (pink, white, or blue) variety.arrow_forwardConsider the following cross: AaBbCcDdEe X AaBbCcDdEe. How many different phenotypes would you expect in the offspring from this cross? Number of phenotypes =arrow_forwardWhen a white guinea pig is crossed to a yellow guinea pig, all the progeny are cream-colored. From a cross of two such F1’s, the F2 showed 32 white, 66 cream, and 30 yellow guinea pigs. How is this trait inherited? _______________ Identify the genotype of the white guinea pig. ________ Identify the genotype of the yellow guinea pig. ________ Identify the genotype of the cream-colored guinea pig. ________ Identify the genotypes and the corresponding phenotypes of the F2 progeny. Give the genotypic ratio. __________________ Give the phenotypic ratio. ___________________arrow_forward
- In snapdragons, red flower color (R) is incompletely dominant over white flower color (r), so that the heterozygote has pink flowers. A red snapdragon is crossed with a white snapdragon, and the F1 are intercrossed to produce F2. What is the genotype and phenotypes of the F1 and F2, along with their expected proportions? If the F1 are backcrossed to the white parent, what will be the expected genotype and phenotype of the offspring? If the F1 are backcrossed to the red parent and the resulting progeny are intercrossed, what is the expected proportions of genotypes and phenotypes in the progeny?arrow_forward. In pea plants, seed shape and seed color are controlled by genes located on different chromosomes. Seeds may be round (R) or wrinkled (r), with the allele for round seeds being dominant. Alleles for seed color are yellow and green, with the green allele (y) recessive to the yellow (Y) allele. If you cross an individual that is homozygous round and yellow with an individual that is homozygous for wrinkled and green, what is the genotype of the F1 individuals?arrow_forwardIn sweet peas, gene C or P alone produces white flowers, the purple colour being due to the presence of both these factors. What will be the flower colour of the offsprings of the following crosses, in which genotypes of parents are given;a) A white flowered plant crossed with a purple produces offspring, of which three-eighth are purple and five-eighth white.arrow_forward
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