Critical Thinking: Did Mendel’s results from plant hybridization experiments contradict his theory?
Gregor Mendel conducted original experiment to study the genetic train of pet plants. In 1865 he wrote “Experiments in Plant Hybridization” which was published in Proceedings of the Natural History Society. Mendel presented a theory that when there are two inheritable trails, one of them will be dominant and the other will be recessive, Each parent contributes one gene to an offspring and, depending on the combination of genes, that offspring could inherit the dominant trait or the recessive trait. Mendel conducted an experiment using pea plants. The pods of pea plants can be green or yellow. When one pea carrying a dominant green gene and a recessive yellow gene is crossed with another pea carrying the same green/yellow genes, the offspring can inherit any one of these four combinations of genes: (1) green / green; (2) green / yellow; (3) yellow / green; (4) yellow / yellow. Because green is dominant rod yellow is recessive, the offspring pod will be green if either of the two inherited genes is green. The offspring can have a yellow pod only if it inherits the yellow gene from each of the two parents. Given these conditions, we expect that 3/4 of the offspring peas should have green pods; that is. P(green pod) = 3/4.
When Mendel conducted his famous hybridization experiments using parent pea plants with the green/yellow combination of genes, he obtained 580 offspring. According to Mendel’s theory, 3/4 of the offspring should have green pods, but the actual number of plants with green pods was 428. So the proportion of offspring with green pods to the total number of offspring is 428/580 = 0.738. Mendel expected a proportion of 3/4 or 0.75, but his actual result is a proportion of 0.738.
a. Assuming that P(green pod) = 3/4, find the probability that among 580 offspring, the number of peas with green pods is exactly 428.
b. Assuming that P(green pod) = 3/4, find the probability that among 580 offspring, the number of peas with green pods is 428 or fewer.
c. Which of the two preceding probabilities should be used for determining whether 428 is a significantly low number of peas with green pods?
d. Use probabilities to determine whether 428 peas with green pods is a significantly low number. (Hint: See “Identifying Significant Results with Probabilities” in Section 5-1.)
Want to see the full answer?
Check out a sample textbook solutionChapter 5 Solutions
Essentials of Statistics (6th Edition)
- Scientist Gregor Mendel (1822-1884) is often called the "father of modern genetics" and is famous for his work involving the inheritance of certain traits in pea plants. Suppose that the genes controlling the color of peas are Y for yellow and y for green. Each plant has two genes, one from the female (seed) and one from the male (pollen). The Y gene is dominant, and therefore a plant with genes YY will have yellow peas, a plant with genes Yy or yY will have yellow peas, and a plant with genes yy will have green peas. If a plant with two yellow genes (YY) is crossed with a plant with two green genes (yy), the result is four hybrid offspring with genotypes Yy. The offspring will be yellow, but will carry the recessive green gene. Parent 2 У Yy Yy Yy Yy y Parent 1 Suppose that both parent pea plants are hybrids with genotype Yy. a. Make a chart showing the possible genotypes of the offspring. b. What is the probability that a given offspring will have green peas? c. What is the…arrow_forwardRetinitis pigmentosa is a disease that manifests itself via different genetic modes of inheritance. Cases have been documented with a dominant, recessive, and sex-linked mode of inheritance. It has been conjectured that mode of inheritance is related to the ethnic origin of the individual. Cases of the disease have been surveyed in an English and a Swiss population with the following results: Of 125 English cases, 46 had sex-linked disease, 25 had recessive disease, and 54 had dominant disease. Of 110 Swiss cases, 1 had sex-linked disease, 99 had recessive disease, and 10 had dominant disease. *10.15 Do these data show a significant association between ethnic origin and genetic type?arrow_forwardBlack bears (Ursus americanus) tend to wander for food, and they have a high level of curiosity. These characteristics will sometimes get them into trouble when they travel through human-use areas such as parks. When they become "nuisances," the Park Service transplants them, if possible, to other areas. The outcomes of such transplants in Glacier National Park over a 10-year period are given in the table below. Given that a black bear was female, what is the probability that it was successfully transplanted?arrow_forward
- A team of researchers is testing the effectiveness of a new HPV vaccine. They randomly divide the subjects into two groups. Group 1 receives the new HPV vaccine, and Group 2 receives the existing HPV vaccine. Neither the patients or the doctors examining them knew which group they were in. Which is the treatment group? O Group 1 O Group 2 O Neither group Which is the control group (if there is one)? O Group 1 O Group 2 O No control group Is this study blind, double blind, or neither? ete O Blind O Double-blind O Neither Novt Ouertionarrow_forwardA team of researchers is testing the effectiveness of a new HPV vaccine. They randomly divide the subjects into two groups. Group 1 receives the new HPV vaccine, and Group 2 receives the existing HPV vaccine. Neither the patients or the doctors examining them knew which group they were in. Which is the treatment group? O Group 1 O Group 2 O Neither group Which is the control group (if there is one)? O Group 1 O Group 2 O No control group Is this study blind, double blind, or neither? O Blind O Double-blind O Neither > Next Question 31arrow_forwardA study is testing the effectiveness of a new allergy medication. Sixty people who reported they experience allergies were randomly assigned to one of two groups: one with the new medication, and another with a placebo. After two weeks, the subjects were surveyed by technicians to determine their level of allergic symptoms. Which of the following would benefit this experiment the most? A. This experiment should be double blind. Neither the subject nor the technician should know which group is receiving the new medication and which is receiving the placebo. This method would control for the placebo effect and prevent any effect on the response. B. This experiment should be single blind. The subjects do not know which treatment they are receiving to control for the placebo effect, but the technicians need to know which group received which treatment. C. This experiment should be single blind. The subjects know which treatment they are receiving but the technicians do not know which…arrow_forward
- Suppose a birth defect has a recessive form of inheritance.In a study population, the recessive gene (a) initially has aprevalence of 25%. A subject has the birth defect if bothmaternal and paternal genes are of type a. A further study finds that after 10 generations (≈200 years)a lot of inbreeding has taken place in the population. Twosubpopulations (populations A and B), consisting of 30%and 70% of the general population, respectively, haveformed. Within population A, prevalence of the recessivegene is 40%, whereas in population B it is 10%. Suppose that a baby is born with a birth defect,but the baby’s ancestry is unknown. What is the posteriorprobability that the baby will have both parents from population A, both parents from population B, or mixed ancestry,respectively? (Hint: Use Bayes’ rule.)arrow_forward2. In a study of hypnotic suggestion, 16 male volunteers were randomly allocated to a treatment group and a control group. Each subject participated in a two-phase experimental session. In the first phase, respiration was measured while the subject was awake and at rest. In the second phase, the subject was told to imagine that he was performing muscular work, and respiration was measured again. For subjects in the treatment group, hypnosis was induced between the first and second phases; thus, the suggestion to imagine muscular work was "hypnotic suggestion" for treatment subjects and "waking suggestion" for control subjects. The table below shows the measurements of total ventilation (liters of air per minute per square meter of body area) for all 16 subjects. Treatment Group Total Ventilation Work Control Group Difference Total Ventilation Difference Work Subject 1 Rest (Work-Rest) Subject Rest (Work-Rest) 5.74 6.24 0.50 9. 6.21 5.50 -0.71 6.79 9.07 2.28 10 4.50 4.64 0.14 3 5.32…arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman