Concept explainers
In a species of plant, two genes control flower color. The red allele
is dominant to the white allele
the color-producing allele
is dominant to the non-color-producing allele
. You suspect that either an
homozygote or a cc homozygote will produce white flowers. In other words,
is epistatic to C, and cc is epistatic to R. To test your hypothesis, you allow heterozygous plants
to self-fertilize and count the offspring. You obtain the following data: 201 plants with red flowers and 144 with white flowers. Conduct a chi square analysis to see if your observed data are consistent with your hypothesis.
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Genetics: Analysis and Principles
- A researcher studied six independently assorting genes in a plant. Each gene has a dominant and a recessive allele: R black stem, r red stem; D tall plant, d dwarf plant; C full pods, c constricted pods; O round fruit, o oval fruit; H hairless leaves, h hairy leaves; W purple flower, w white flower From the cross (P1) RrDdccOoHhWw x (P2) RrddCcooHhww, determine: Note: RrDdccOoHhWw is one genotype. a. How many kinds of gametes can be formed by P1?b. How many genotypes are possible among the progeny of this cross?c. How many phenotypes are possible among the progeny?d. What is the probability of obtaining the RrDdccOohhww genotype in the progeny?e. What is the probability of obtaining a black, dwarf, constricted, oval, hairy, purple phenotype in the progeny?arrow_forwardIn a certain type of pea plant, the gene for yellow color (Y) is dominant to the gene for green color (y), and the gene for round shape (R) is dominant to the gene for wrinkled shape (r). If a homozygous dominant plant is mated with a homozygous recessive plant (P-gen), what proportion in the F2 generation will be homozygous recessive? a) 1/4 b) 1/16 c) 3/4 d) 3/8arrow_forwardThe shape of a pumpkin is determined by the action of two genes A and B. The recessive forms of these two alleles produces a flattened-shaped fruit, whereas the dominant forms of these two alleles produce the typical pumpkin with ridges. When both alleles are heterozygous a disc-shaped pumpkin is produced. If the genotype of the pumpkin plant is homozygous dominant at one allele and heterozygous at the other, the pumpkin will be ball-shaped. If the pumpkin plant is homozygous recessive at one allele and heterozygous at the other allele it produces an oblong-shaped fruit. Plants with genotypes other than the ones listed in this question do not produce pumpkins. Do the following cross: two pumpkin plants capable of making disc-shaped pumpkins are crossed with each other. Based on this cross, answer the following: (Show your work below.) How many of the progeny will make ball-shaped pumpkins?__________________________________________ How many of the progeny will make disc-shaped…arrow_forward
- If a cross is made between two plants that are heterozygous for two traits (AaBb), then their offspring should follow the 9:3:3:1 ratio. In this case, A is the dominant allele for purple leaves, and B is the dominant allelle for curly roots. If the two parents were crossed to yield 320 progeny, approximately how many plants with purple leaves and curly roots would you expect? Group of answer choices a.180 b.225 c.25 d.50 As part of a lab experiment, you create a two-locus cross between two plants, and you expect to see a 8:4:2:2 ratio of offspring. You determine the phenotype for 160 offspring, and find the proportions 84:38:19:19. If you use a chi-square test to determine whether the offspring do indeed fit this pattern, how many degrees of freedom would the test have? Group of answer choices a.2 b.3 c.83 d.4arrow_forwardSunflowers with flowers 10 cm in diameter are crossed with a plant that has 20-cm flowers. The F1 plants have flowers 15 cm in diameter. In the F2 generation, 4 flowers are 10 cm in diameter and 4 are 20 cm in diameter. Between these are 5 phenotypic classes with diameters intermediate to those at the extremes. a. Assuming that the alleles that contribute to flower diameter act additively, how many genes control flower size in this strain of sunflowers? b. How much does each additive allele contribute to flower diameter? c. What size flower makes up the largest phenotypic class?arrow_forwardGenes A and B are 6 map units apart, and A and C are 4 map units apart. Which gene is in the middle if B and C are 10 map units apart? Which is in the middle if B and C are 2 map units apart?arrow_forward
- The trait for medium-sized leaves in iris is determined by the genetic condition PP'. Plants with large leaves are PP, whereas plants with small leaves are P'P'. The trait for red flowers is controlled by the genes RR, pink by RR', and white by R'R'. A cross is made between two plants each with medium-sized leaves and pink flowers. If they produce 640 seedlings, what would be the expected phenotypes, and in what numbers would they be expected? View keyboard shortcuts EditViewInsertFormatToolsTable 12pt Paragrapharrow_forwardGene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele have sharp spines, whereas homozygous recessive cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have long or short spines. Homozygous recessive cactuses have short spines. A cross between a homozygous sharp-long cactus and a dull short-spined cactus would produce what percentage of sharp-long cacti?arrow_forwardGene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele have sharp spines, whereas homozygous recessive cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have long or short spines. Homozygous recessive cactuses have short spines. A cross between a homozygous sharp-long cactus and a dull short-spined cactus would produce what percentage of sharp-long cacti? Show your Punnett square please.arrow_forward
- A mapping experiment in strawberries shows that the genes for color and plant height are separated by 16cM. In a cross between a heterozygous plant (CcHh) and a homozygous recessive plant, what percent of offspring would inherit a chromosome carrying cH from the heterozygous parent.... 1. if the heterozygous parent’s alleles are in repulsion? _________________ 2. if the heterozygous parent’s alleles are in coupling? _________________arrow_forwardIn the Primula plant, the blue flower color is due to malvidin, a pigment encoded by the completely dominant gene (M). Presence of only the recessive gene (m) leads to white flowers. The P locus controls pigment synthesis in the M locus such that dominant gene (P) stops pigment production, and recessive gene (p) allows pigment production. Two plants both having the MmPp genotype were crossed. What would be the probability of getting plants that are pure-breeding for blue flower color?arrow_forwardSuppose two independently assorting genes are involved in the pathway that determines fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store. At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for a colored squash. At the second locus, the allele Y codes for a dominant yellow phenotype, and the allele y codes for a recessive green phenotype. The phenotypes from the first locus will always mask the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis. A dihybrid squash, Ww Yy, is selfed and produces 160160 offspring. How many offspring are expected to have the white, yellow, and green phenotypes?arrow_forward
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