To review:
There are many varieties of rice that are tolerant or intolerant to floods. The true breeding-intolerant varieties are
1. Results of the cross |
Number of plants | ||
Tolerant (Alive) | Intolerant (Dead) | Total | |
On the basis of the data given for the various crosses, justify that it supports that tolerance is a dominant trait with the help of genotypes and phenotypes.
Introduction:
A cross used to determine the phenotypes of parents is known as a test cross. The parent plant is crossed with the plant with the recessive genotype. If the ratio of dominant to recessive in the progeny is 3:1, the parent is true-breeding dominant, whereas if the ratio is
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Chapter 12 Solutions
Biology: The Dynamic Science (MindTap Course List)
- Half of the worlds population eats rice at least twice a day. Much of this rice is grown in flooded conditions, and different strains of rice are tolerant (survive) or intolerant (die) under these conditions. Rice breeders used genetic crosses to test whether tolerance to flooding is a dominant trait. Researchers used three true-breeding flood-tolerant strains, FR143, BKNFR, and Kurk, and two true-breeding flood- intolerant strains, IR42 and NB, in the crosses. Results were obtained from three sets of crosses and are reported in the Table below: Results of cross of F1 to tolerant parent: F1 plants were crossed with the tolerant parent of the cross. Number of Plants Progeny Analyzed from Intolerant Tolerant Cross Alive Dead Total 1. F2 results of cross: IR42 FR13A 187 77 264 IR42 BKNFR 192 73 265 NB Kurk 142 52 195 2. Results of cross of F1 to intolerant parent: (F1 of IR42 FR13A) IR42 14 17 31 (F1 of IR42 BKNFR) IR42 15 10 25 (F1 of NB Kurk) NB 21 35 56 3. Results of cross of F1 to tolerant parent: (F1 of IR42 FR13A) FR13A 31 0 31 (F1 of IR42 BKNFR) BKNFR 28 0 28 (F1 of NB Kurk) Kurk 40 0 40 Do the data support the hypothesis that the tolerance trait is dominant? Justify your conclusion by explaining the results from each of the three sets of crosses in terms of genotypes and phenotypic ratios. Source: T. Setter et al. 1997. Physiology and genetics of submergence tolerance in rice. Annals of Botany 79:6777.arrow_forwardIn a population of flowers growing in a meadow, C1C1 and C2C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with ff (C1)(C1) = 0.8 and ff (C2)(C2) = 0.2. Flowers that are C1C1C1C1 are yellow, orange flowers are C1C2C1C2, and C2C2C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1C1C1 = 0.30, C1C2C1C2 = 0.60, and C2C2C2C2 = 1.0. A. Assuming the population begins in H−WH−W equilibrium, what is C1C1 allele frequency after one generation of natural selection? B.Assuming the population begins in H−WH−W equilibrium, what is C2C2 allele frequency after one generation of natural selection? C.arrow_forwardThere are two incomplete-dominant alleles for petal color in a population of flowers. 36% of the flowers have red petals, 16% of the organisms have white petals, and 48% of the flowers have pink petals. What percentage of alleles in this population code for red petals (R)? how can i calculate it?arrow_forward
- You are studying a population of penguins in Antarctica. Your DNA analysis of this population reveals that for the feather color pattern gene, 35 individuals are homozygous dominant, 35 individuals are heterozygous, and 30 individuals are homozygous recessive. After observing this population for several years, you repeat your DNA study and find that the current generation of penguins has 15 individuals that are homozygous dominant, 10 individuals that are heterozygous, and 75 individuals that are homozygous recessive. Which of the following hypotheses for this data would be supported by this data based on your understanding of Hardy-Weinberg equilibrium? This population of penguins is maintaining Hardy-Weinberg equilibrium due to its large population size. The penguins are randomly choosing mates, which has led to Hardy-Weinberg equilibrium. The penguins are very isolated, which is preventing gene flow from affecting Hardy-Weinberg equilibrium. The recessive phenotype in…arrow_forwardYour parents are studying the evolution of the pumpkin size to make the best patch in your city. After doing some crosses and genotyping some individuals, you determined that the number of individuals homozygous dominant for the largest pumpkin allele is 98, 80 are heterozygous for medium size, and 20 are homozygous recessive for small size. What is the allele frequency for the homozygous dominant allele? Please round up and your final answer should have four decimal points.arrow_forwardHow Can We Measure Allele Frequencies in Populations? In a population where the females have the allelic frequencies A = 0.35 and a = 0.65 and the frequencies for males are A = 0.1 and a = 0.9, how many generations will it take to reach HardyWeinberg equilibrium for both the allelic and the genotypic frequencies? Assume random mating and show the allelic and genotypic frequencies for each generation.arrow_forward
- Using the HardyWeinberg Law in Human Genetics In a given population, the frequencies of the four phenotypic classes of the ABO blood groups are found to be A = 0.33, B = 0.33, AB = 0.18, and i = 0.16. What is the frequency of the i allele?arrow_forwardA meadow is home to a population of plants of a particular species. Among these individuals are 125 plants that have red flowers and 375 plants that have white flowers. The allele of the flower color gene that produces red flowers (R) is completely dominant over the white flower color allele (r). If a plant with red flower color is crossed with a plant that produces all white flowers, what is the probability that the offspring will include plants that have white flowers? Group of answer choices a. 50% chance b. 75% chance c. 0% chance d. 25% chance e. There is not enough information to say.arrow_forward. In pea plants, height is controlled by a Dominant Allele (T) for Tall Height and by a Recessive Allele (t) for Short Height. If 96% of a population of pea plants have the tall phenotype, calculate the frequencies of dominant allele (T) & recessive (t) alleles. Out of the 96%, what is the estimation of how many are homozygous dominant vs. heterozygous? What is the frequency of the recessive phenotype?arrow_forward
- Among a particular population of 100 plants, red flowers are dominant and yellow flowers are recessive. F is the dominant allele and f is the recessive allele. 40 plants are homozygous dominant • 44 plants are heterozygous 16 plants are homozygous recessive Use the Hardy-Weinberg equation to calculate the equilibrium frequencies of each genotypearrow_forwardIn reference to the following table: F1 ebony flies - 0 F1 non-ebony flies - 560 F1 stubbly flies - 560 F1 non-stubble flies - 0 State whether the allele in the populations giving rise to each phenotype (stubble bristle and ebony bodies) is dominant or recessive.arrow_forwardWhich of the following is not an example of artificial selection? (a) Your younger sibling got a hamster as a birthday present, and it turned out to be pregnant. Several of the offspring had long, silky hair, and your sibling put them together in an enclosure to try to produce more baby hamsters with long, silky hair. Your sibling continued to breed long- and silky-haired hamsters to each other and now, several years later, your sibling’s bedroom is full of cages containing long- and silky-haired hamsters. (b) Your mother has been saving the best seeds from her lima bean plants every summer and replanting them the next year. She likes seeds that are plump and bright green and saves only these each year. Within 10 years, almost all of her lima beans have become plump and bright green. (c) Farmer Brown has a duck that can type. He sets up an online dating profile for his duck to find a female duck that can also type. Seven years after the arranged wedding of the two typing ducks, Farmer…arrow_forward
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