Imagine you are a forensic investigator giving a presentation to a school assembly. A student asks you, “If people have such a similar genetic makeup, then why do you use DNA to understand whether suspects are innocent or guilty of a crime?” In 1–2 sentences, describe how you might answer the student’s question.
Genetic Variation: Genetic Variation Unit Test (Unit 2, lesson 13)
1. Which statement best describes the process of crossing over?
A: Homologous chromosomes pair up, and non-sister chromatids exchange genetic material.
2. A student is completing a Punnett square for a trait (X/x) that is autosomal and inherited by the dominant allele. The father does not have it (xx), but the mother does (Xx). If they had two children, a son and a daughter, what would the completed Punnett square look like (i.e., would the son have the trait, would the daughter have the trait)?
A: Each child has a 50% chance of inheriting the trait.
3. Which cell replicates via meiosis?
A: sperm cell
4. This is the original strand of DNA: ATG AAG TTT GGC TAA
Which option would represent a frameshift mutation due to deletion during replication?
B: ATG AAG TTG GCT AA
5. How are genotypes and phenotypes related?
C: Genotypes determine the phenotypes expressed.
6. Do mutations in body cells contribute to genetic variation?
D: No, the mutations cannot be passed to offspring and only affect the individual.
7. A garden contains 40 flowers, 30 of which are red. What is the frequency of red flowers?
C: 0.75
8. A tall pea plant results from a dominant tall allele while the short phenotype results from two recessive alleles. What is the frequency of short offspring (pp) when a tall pea plant with one tall allele (Pp) is cross-pollinated with a short pea plant (pp)?
B: 0.5
9. In a moth population, 47 are brown, 15 are yellow, and 34 are black. What is the approximate probability of a moth being black? (Round your answer.)
A: 35%
10. What is the term used to describe any living or nonliving things that influence another living organism?
B: Environmental factors
***THESE ANSWERS HAVE YET TO BE GRADE***
11. Hypothesize how some people have red hair through viable errors. Explain your answer in 1-2 sentences.
**Answer: Some people have red hair through viable errors due to mutations in the genetic code. The cells that suffer these mutations would not be able to sustain life. The mutation that causes red hair is a mutation in the gene responsible for melanin and isn't one that affects an essential process.
12. Imagine you are a forensic investigator giving a presentation to a school assembly. A student asks you, “If people have such a similar genetic makeup, then why do you use DNA to understand whether suspects are innocent or guilty of a crime?” In 1–2 sentences, describe how you might answer the student’s question.
**Answer: I would answer by stating, "While it may look like people have similar genetic makeup, there are actually enough differences in our DNA from person to person, even identical twins, that can be used to identify an individual."
13. In 1-2 sentences, explain why mutations can be beneficial to an organism.
**Answer: Genetic mutations can be beneficial because it can help evolution by introducing new genetic variation into the population. Which can then increase the chances of survival in a changing environment.
14. Salt is notoriously dangerous to land snails; however, some populations of aquatic, freshwater snail have brackish (or a mix of salt and fresh water) water adaptations and live in different parts of a river system. A group of scientists monitored salt concentrations in the habitats of two freshwater snail populations located nearby and recorded the salt level as follows (in ppt, parts per thousand):
Population 1 (Day 1): 0.1 ppt (morning), 0.0 ppt (afternoon), 0.1 ppt (evening)
Population 2 (Day 1): 0.3 ppt (morning), 0.5 ppt (afternoon), 0.2 ppt (evening)
In 3–5 sentences, 1) describe in which population you'd expect to see more adaptations for salt water and 2) explain how such adaptations would become more common in this population.
**Answer: Population 2 would be expected to have more adaptations for salt water, as the salt concentration is higher than in Population 1. Over time, these adaptations would become more common in Population 2 as individuals with the adaptations would be more likely to survive and reproduce in the higher salt concentration environment. As a result, the adaptations would become more common in the population as the individuals with the adaptations would pass them on to their offspring.
15. One of the effects of climate change is the warming of ocean and air temperatures. The sex of sea turtle offspring is determined by temperature during development. Temperature over 87° Fahrenheit will result in female offspring. In 2-5 sentences, describe what change you'd expect to see in the distribution of traits, if any, and whether it would be caused by a genetic adaptation, a mutation, or the environment.
**Answer: There will be more female offspring because the effects of climate change are the warming of the ocean and air temperatures. Over time if it gets to the point where there are far more females than males, this could cause a disruption in the population.