Concept explainers
FROM DATA TO DECISION
Critical Thinking: Did Mandal’s results from plant hybridization experiments contradict his theory?
Gregor Mendel conducted original experiments to study the genetic train of pea plaits. 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, 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/yd low 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 and 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, bat the actual number of plants with green pods was 428. So the proportion of offspring with green pods to the total number of offspring b 428/580 = 0.738. Mendel expected a proportion of 3/4 or 0.75, but his actual mull is a proportion off 0.738.
- a. Assuming that P(green pod) = 3/4, find the probability that among 580 offspring, the number of peas with green pods b exactly 428.
- b. Assuming that P(green pod) = 3/4. find the probability that among 580 offspring, the number of peas with green pods b 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.)
Trending nowThis is a popular solution!
Chapter 5 Solutions
Essentials of Statistics Plus MyLab Statistics with Pearson eText - Access Card Package (5th Edition)
- Biologists wish to mate pairs of fruit flies having genetic makeup RrCc, indicating that each has one dominant gene (R) and one recessive gene (r) for eye color, along with one dominant (C) and one recessive (c) gene for wing type. Each offspring will receive one gene for each of the two traits from each parent, so the biologists predict that the following phenotypes should occur in a ratio of 9:3:3:1. Phenotype Frequency Red eyes and Red eyes and straight wings curly wings 99 42 White eyes and straight wings 49 White eyes and curly wings 10 Use a chi-square goodness-of-fit test to compute a test statistic and P-value. At the a = 0.05 significance level, what can be concluded about the proposed genetic model? Because the P-value of 0.1029 > 0.05, we cannot reject the null hypothesis. We do not have convincing evidence that the distribution of eye color and wing shape is different from what the biologists predict. Because the P-value of 0.5177 > 0.05, we cannot reject the null…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_forward1. According to a certain Mendelian genetic model, self-pollination of pink-flowered plants should produce progeny that are red, pink, and white in the ratio 1:2:1. A geneticist self-pollinated pink-flowered snapdragon plants and produced 234 progeny with 54 red, 122 pink and 58 white flowered plants. To test if these numbers indeed follow the model ratio, what should be an appropriate null hypothesis? A. P(Red) = 54/234, P(Pink) = 122/234, P(White) = 58/234. B. P(Red) = 54%, P(Pink) = 122%, P(White) = 58%. C. P(Red) = 1, P(Pink) = 2, P(White) = 1. D. P(Red) = 0.25, P(Pink) = 0.5, P(White) = 0.25. 2. What would be the degree of freedom for an appropriate test? A. 3 B. 2 C. 1 D. 0 3. If we fail to reject the null hypothesis at 0.05 significance level, what do you conclude? A. The self-pollinated plants of the geneticist do not follow the ratio 1:2:1 and this validates the model. B. The self-pollinated plants of the…arrow_forward
- As mentioned in Experimental Question E11, red eyes is the wildtype phenotype. Several different genes (with each gene existing intwo or more alleles) are known to affect eye color. One allelecauses purple eyes, and a different allele causes sepia eyes. Both ofthese alleles are recessive to red eye color. When flies with purpleeyes were crossed to flies with sepia eyes, all of the F1 offspringhad red eyes. When the F1 offspring were allowed to mate witheach other, the following data were obtained:146 purple eyes151 sepia eyes50 purplish sepia eyes444 red eyesExplain this pattern of inheritance. Conduct a chi sqarrow_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? ete O Blind O Double-blind O Neither Novt Ouertionarrow_forward3.Luijckx et al (2012) discovered that resistance to the bacterial parasite Pasteuria ramose is genetically variable in the common freshwater crustacean, Daphnia magna. To investigate the genetic basis of this variation, they crossed a completely resistant lineage to a completely susceptible lineage. All the F1 offspring were resistant. These offspring, when mature, were then crossed to each other to produce an F2 generation. If resistance is the result of only a single gene with two forms (alleles) then resistant and susceptible F offspring should occur in a 3:1 ratio. Of 71 F2’s tested, 57 were resistant and 14 were susceptible. a.With these data, calculate the range of most plausible-values for the proportion of resistant offspring. Does the plausible range include the proportion predicted if resistance is determined by a single gene? b.Give two other values for proportion that are also consistent with the data. c.Test the genetic hypothesis. Are the results compatible with the…arrow_forward
- An experiment in chicken breeding results in offspring having very curly, slightly curly, or normal feathers. If this is the result of a single gene system, then the proportions of offspring in the three phenotypes should be 0.25, 0.50, and 0.25 respectively. In one such experiment, 93 chickens were born. 20 had normal feathers, 50 had slightly curly feathers, and 23 had very curly feathers. Carry out a test to determine whether the genetic model seems to hold in this setting.arrow_forwardA goodness-of-fit test is designed to deal with multiple categories at once. See Section 6.7 for more details. A crop researcher investigated the phenotypes that resulted from crossing two different types of tomato plants. There are 4 possible resulting phenotypes (numbered 1, 2, 3, 4 in the data table below). Mendel's laws of genetic inheritance ('the model') suggest that the proportions should be 9/16, 3/16, 3/16 and 1/16 for phenotypes 1, 2, 3, 4 respectively. The classification of a sample of 1611 observations is given below together with the proportions suggested by Mendel's laws of inheritance (the model). According to the model, what is the expected number of observations in this sample that would be Phenotype 4? Expected number =arrow_forwardResearchers were interested in studying the relationship between living location (Manhattan vs. other boroughs of NYC) and anxiety. Researchers decided to randomly select 50 residents from Manhattan and 40 residents from the other four boroughs. All were free from anxiety disorders at the start of the study. They then followed the participants for three years to determine how many in each group developed an anxiety disorder. Among residents of Manhattan, 18 out of 50 developed an anxiety disorder. Among residents of the other four boroughs, 12 out of 40 developed an anxiety disorder. Question : The risk of developing an anxiety disorder for those living in Manhattan was _______ times the risk of developing an anxiety disorder for those living in the other boroughs.arrow_forward
- 2. If an individual with the genotype Yy Ww Pp ee Bb is crossed with another individual with the same genotype, what proportion of offspring will be homozygous recessive at all genes? Answers: 1/1024 5/128 1/256 3/16 1/16 3. If an individual with genotype Yy Ww Pp ee Bb is crossed with an individual with the same genotype, what proportion of offspring will have the dominant phenotype for the four heterozygous loci? answers: 81/256 81/128 27/256 3/16arrow_forwardIt is now generally accepted that cigarette smoking causes heart disease, lung cancer, and many other dis- eases. However, in the 1950s, this idea was controversial. There was a strong association between smoking and ill-health, but association is not causation. R. A Fisher advanced the "constitutional hypothesis: there is some genetic factor that disposes you both to smoke and to die. To refute Fisher's idea, the epidemiologists used twin studies. They identified sets of smoking-discordant monozygotic twin pairs. "Monozygotic" twins come from one egg and have identical genetic makeup; "smoking-discordant" means that one twin smokes, the other does not. The researchers collected data on which twin dies first, the smoker or the non-smoker. The data from a Finnish twin study are shown in the following table. Smokers Non-smokers All Causes 17 5 Coronary heart disease Lung Cancer 9 According to the first line of the table, there were 22 smoking-discordant monozygotic twin pairs where at…arrow_forwardQuestion 1 > Dogs are inbred for such desirable characteristics as blue eye color; but an unfortunate by-product of such inbreeding can be the emergence of characteristics such as deafness. A 1992 study of Dalmatians (by Strain and others, as reported in The Dalmatians Dilemma) found the following: (i) 31% of all Dalmatians have blue eyes. (ii) 38% of all Dalmatians are deaf. (iii) 42% of blue-eyed Dalmatians are deaf. What is the probability that a randomly chosen Dalmatian is blue-eyed and deaf? .31 * .38 = .1178 O.31 * .42 = .1302 .38 * .42 = .1596 .31 / .38 = .8158 0.31 / .42 = .7381 0.38 / .42 = .9048 Submit Questionarrow_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