LAB 03 CRITICAL THINKING

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LAB 03 CRITICAL THINKING QUESTIONS Due No due date e Points 15 e Questions 15 e Time Limit None Attempt History Attempt Time Score LATEST Attempt 1 32 minutes 7 out of 15 Score for this quiz: 7 out of 15 Submitted Feb 21 at 11:26am This attempt took 32 minutes. Question 1 1/1 pts (Q001) Describe the two laws of inheritance put forward by Gregor Mendel. For each, also describe how you think modern genetics has clarified or supported these early concepts. Your Answer: Gregor Mendel proposed two laws of inheritance: the Law of Segregation and the Law of Independent Assortment. Law of Segregation states that during gamete formation, pairs of alleles separate so that each gamete receives one allele from each parent. Law of Independent Assortment states that genes for different traits are sorted independently of each other during gamete formation. Modern genetics has supported these early concepts by demonstrating that allele segregation is determined by the number of chromosomes and the law of independent assortment is determined by the genes being on different chromosomes. Question 2 0/1pts (Q002) Use the Punnett squares you completed in Exercise 1 on p.69 of your lab manual to answer Parts a and b. Part a. Timmy was homozygous dominant for the freckles trait. Looking at the Punnett square for his parents’ mating, what was the probability of Timmy having a different genotype? What was the probability of Timmy having a different phenotype?

different genotype: 0%, different phenotype: 0% You Answered different genotype: 25%, different phenotype: 75% Correct Answer different genotype: 75%, different phenotype: 25% different genotype: 50%, different phenotype: 50% FEEDBACK: Looking at the Punnett square for his parents' mating, Timmy had a 75% chance of having a different genotype (50% chance of Ff; 25% chance of ff). Howeuver, since having a genotype of Ff would have given him the same phenotype, there was only a 25% chance of having a different (recessive) phenotype. Question 3 1/1 pts (Q003) Part b. Timmy's mother was heterozygous for the freckles trait. Looking at the Punnett square for his grandparents' mating, what was the probability of Timmy's mother having a different genotype? What was the probability of Timmy's mother having a different phenotype? Correct! different genotype: 0%, different phenotype: 0% different genotype: 25%, different phenotype: 75% different genotype: 75%, different phenotype: 25% different genotype: 50%, different phenotype: 50% FEEDBACK: Looking at the Punnett square for the grandparents' mating, Timmy's mother had a 0% chance of having a different genotype. Her mother was homozygous recessive whereas her father was homozygous dominant, which means that all their children could only be heterozygous for trait F. Since Timmy's mother had a 0% chance of having a different genotype, she also has a 0% chance for having a different phenotype. Question 4 0/1pts (Q004) Complete the chart on p. 79 of your lab manual comparing Punnett squares and pedigree diagrams. For each characteristic, indicate whether Punnett squares, pedigree diagrams, or both have that characteristic by placing a mark in the appropriate column. Answer Parts i-viii about the chart. Part i. Which show one mating at a time? Correct Answer Punnett squares pedigree diagrams

You Answered both Punnett squares and pedigree diagrams FEEDBACK: Punnett squares only show one mating at a time, whereas pedigree diagrams show more than one mating. Question 5 0/1pts (Q005) Part ii. Which show multiple generations at a time? You Answered Punnett squares Correct Answer pedigree diagrams both Punnett squares and pedigree diagrams FEEDBACK: Pedigree diagrams show multiple generations at a time, whereas Punnett squares show only one generation. Question 6 1/1 pts (Q006) Part iii. Which show phenotypes? Punnett squares Correct! pedigree diagrams both Punnett squares and pedigree diagrams FEEDBACK: Pedigree diagrams show phenotypes, whereas Punnett squares do not. Question 7 0/1pts (Q007) Part iv. Which require you to infer phenotypes? Correct Answer Punnett squares pedigree diagrams You Answered both Punnett squares and pedigree diagrams

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FEEDBACK: Punnett squares require you to infer phenotypes, whereas pedigree diagrams show you the phenotypes directly. Question 8 0/1pts (Q008) Part v. Which show genotypes? Correct Answer Punnett squares You Answered pedigree diagrams both Punnett squares and pedigree diagrams FEEDBACK: Punnett squares show you genotypes, whereas pedigree diagrams do not. Question 9 0/1pts (Q009) Part vi. Which require you to infer genotypes? You Answered Punnett squares Correct Answer pedigree diagrams both Punnett squares and pedigree diagrams FEEDBACK: Pedigree diagrams require you to infer genotypes, whereas Punnett squares show you genotypes directly. Question 10 0/1pts (Q010) Part vii. Which show real individuals? You Answered Punnett squares pedigree diagrams Correct Answer both Punnett squares and pedigree diagrams FEEDBACK: Both Punnett squares and pedigree diagrams show real individuals. The parents included in Punnett squares are real individuals, whereas all individuals in pedigree diagrams are real.

Question 11 0/1 pts (Q011) Part viii. Which show potential individuals? Correct Answer Punnett squares You Answered pedigree diagrams both Punnett squares and pedigree diagrams FEEDBACK: The offspring shown in Punnett squares are potential individuals. Question 12 1/1 pts (Q012) In this lab, we explored Mendelian traits in humans. Now, let's consider another Mendelian trait: earlobe attachment. Review the images on page 80 of your lab manual that depict the earlobes of different individuals. Naveen is a biological anthropologist investigating the possibility of variation within this trait. He generates a hypothesis: If earlobe attachment is a Mendelian trait, then there will be two, distinct phenotypic expressions (attached earlobes and unattached earlobes). What data would you collect to help Naveen test this hypothesis? (Be sure to specifically describe any potential measurements you would take and what tools would be used to collect these data.) Imagine that you have now collected these data. What patterns in the data would support the hypothesis? (For example, "The hypothesis would be supported if we found data that indicated ) What patterns in the data would cause you to reject the hypothesis? (For example, "The hypothesis would be rejected if we found data that indicated .") Based on what you learned in this lab, do you think humans have numerous, clearly Mendelian traits? Why or why not? Your Answer: We now focus on earlobe attachment as we continue our investigation of Mendelian features in humans. Naveen is a biological anthropologist who is looking into the potential for variation in this characteristic. According to his theory, earlobe attachment might manifest itself in two different ways: attached and unattached. In order to verify this theory, information would need to be gathered by looking at people's earlobes and noting whether or not they are attached. Calipers would be used to measure each earlobe precisely in order to ascertain its attachment condition. The hypothesis would be supported by patterns in the data, such as individual differences in the attachment or lack thereof of their earlobes. On the other hand, the theory would be rejected if the two phenotypes could not be distinguished from one another.

Given what we've learnt in this lab, the predictable patterns in genetic inheritance suggest that humans have many distinctly Mendelian features. Nevertheless, phenotypic expression can also be influenced by environmental influences, which might result in some diversity within these features. Question 13 1/1 pts (Q013) In this lab, we explored sex-linked traits. Use books and resources in your classroom (or reputable online sources) to identify another example of a sex-linked trait in humans. What is the trait? What are the genetic variants? How common is the trait in XY males? and in XX females? How does its commonness compare with that of the red-green color blindness example discussed in this lab? Your Answer: We explored the intriguing realm of sex-linked characteristics in our lab, concentrating on red-green color blindness in particular. But humans also exhibit a wide range of additional sex-related characteristics. Hemophilia, a bleeding disorder that impairs the blood's capacity to clot correctly, is one instance. A mutation in the X chromosome-based genes that produce clotting factors VIl or IX results in hemophilia. Because females have two X chromosomes and males only have one, hemophilia is far more common in XY males than in XX females. Hemophilia affects about 1 in 5,000 male births as opposed to 1 in 50,000 female births. Approximately 1 in 12 males and 1 in 200 females suffer with red-green color blindness; hemophilia is much less common than this condition. This striking distinction draws attention to the diversity and intricacy of sex-related characteristics in people. Question 14 1/1 pts (Q014) Review your results from the dihybrid cross in Exercise 10. Did the inheritance of one trait affect the likelihood of inheriting the other trait? For example, was Suzy and Jose's child more likely to have a widow's peak if it also had freckles? How does the relationship between the two traits support Mendel's law of independent assortment? Your Answer: It is clear from looking over the dihybrid cross findings in Exercise 10 that getting one trait did not change the chance of inheriting the other trait. For instance, the presence of freckles in the kid of Suzy and Jose did not increase the likelihood of a widow's peak. This provides credence to Mendel's Law of Independent Assortment, which postulates that alleles conferring distinct traits are inherited separately from one another. The connection between these two features shows how genes encoding distinct behaviors are inherited at random and unrelated to one another. This indicates that a person does not always have a genetically

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connected trait for another trait just because they have one. This supports Mendel's ground-breaking discovery of how traits are inherited and consistently transmitted down across generations. Question 15 1/1 pts (Q015) Miss Primrose breeds dogs to show in competitions. Her prized female dog, named Stella, recently had an unexpected litter of puppies. Two of the puppies have an unusual coat color called agouti, where each hair has numerous dark and light bands and a dark tip. Miss Primrose specifically bred Stella with another prize-winning dog named Max, but neither Stella nor Max has the agouti fur trait. Miss Primrose suspects that Stella may have been secretly impregnated by a stray dog she has seen in their neighborhood who does have an agouti coat. Miss Primrose collected the following research and pedigree information on Stella and Max: * The non-agouti coat trait (N) is dominant over the agouti coat trait (n). e Stella does not have an agouti coat. e Neither of Stella's parents has an agouti coat. e Stella's maternal grandfather does not have an agouti coat, but Stella's maternal grandmother does have an agouti coat. e Max does not have an agouti coat. e Max's mother does not have an agouti coat, but Max's father does have an agouti coat. Based on this information, is it possible that Max is the father of this litter of puppies? Why or why not? (Hint: It might be helpful to make a pedigree diagram of Stella's and Max's families so you can determine their genotypes and the possibility of their having agouti puppies.) Your Answer: It seems improbable that Max is the father of Stella's litter of puppies with the odd agouti coat color based on the information supplied. It appears that both Stella and Max carry the dominant non-agouti gene because neither of them exhibits the agouti coat characteristic. Stella does not carry this recessive gene, as further evidenced by the fact that neither her parents nor her maternal grandpa exhibit the agouti coat feature. Stella's maternal grandmother, on the other hand, does carry at least one copy of the recessive gene, as seen by her agouti coat. This implies that Stella might also be carrying a secret copy of this gene. It's possible that Max's father carries a copy of the recessive gene for this characteristic because he has an agouti coat. That being said, it is hard to say if Max could be the father of these agouti puppies without knowing his exact genotype. In conclusion, it appears more likely that a stray dog in their neighborhood with an agouti coat may have secretly impregnated Stella than that Max is the father of these unusual puppies based on pedigree analysis and genetic principles. Quiz Score: 7 out of 15

LAB 03 CRITICAL THINKING

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