- The purpose of this interview was to gain an idea of how much knowledge young people retain about genetics. If they do not major in the sciences at a college or university, most students are not exposed to biological sciences beyond their freshman or sophomore year of high school. The constructivist approach to education dictates that every student learns in his or her own unique way, according to individual thought processes, environment, and experience. Clinical studies are an essential part of this pedagogical philosophy because they reveal whatever concepts students already hold on a particular topic. By becoming cognizant of students’ prior knowledge, teachers can work with their existing schemas in order to make correct information more comprehensible and memorable. Clinical studies, like the interviews completed for this assignment, are the first step in a chain of events that may begin with student misconception but can potentially end in student understanding.
- The interview was organized into “three tasks” that participants were asked to complete. Each of the three tasks was related to a topic under the larger category of genetics. The first task was centered on students’ understanding that proteins come from genes and that these proteins are responsible for physical traits. The second task was meant to unearth any elementary understanding of the results and effects of meiosis. The third task was designed to assess students’ comprehension of mutation and its possible effects. Paper and pencil were provided and the participants were encouraged to use them as an aid to help them further express their ideas. Each interviewee answered all of the questions; there were four main questions under task one, seven under task two, and five under task three. Even though all of the questions were presented to the interviewees, some of them were dealt with more quickly than others. When participants just did not know the answer, and they could not be pressed to think further, they had to progress on to the next question. Other questions warranted some “definitive answers” from the students. These occurrences are noted in the main summary.
- Task one focused on the students’ awareness that genes make proteins, and that proteins are responsible for physical traits. This understanding was assessed by first asking the participants general questions, such as “Why do you think baby puppies look like their parents?”, and then gradually progressing to more complex questions such as “What do you think genes do?”
The student’s prior knowledge of genetics:
- Students understood the fact that genes get passed on from generation to generation ex: One of Ruth’s subjects said the following; “genes are certain things that you get from Mom and Dad.”
- Students understood that they inherit their physical traits from their parents. For example, one of the interview subjects said the following: “I’m not sure about the mechanism, but I know that my mother passed the ‘short’ and ‘allergic to everything’ gene to me.”
- Students understood and recognized that genes or DNA led to physical traits
The students lack of understanding of genetics:
- The subjects did not realize that genes are made up of DNA, which code for a functional protein
- Students didn’t understand that traits and genes are two different entities. Students used the words traits and genes interchangeably. Ex: When Edgar asked his students “Do offspring get the same number of traits from each parent?” They gave responses like: S2: “Traits are passed through chromosomes”, S1: “Yes, egg and sperm are reproductive agents that pass chromosomes to offspring”, S3: “They get the same number of traits but not all of them are expressed”. This quote proves they mean to say genes sometimes and traits other times, but do not have a strong definition of either entity. .
- The subjects were not able to explain that DNA encodes for proteins which express traits.
- The patterns that were found in this experiment are actually very common, according to research in some educational journals. In a comprehensive study about student understanding of genetic concepts, Marbach and his colleagues found that students displayed some serious confusion with some very basic biological facts (Insert name of Journal and Year it was published here). Some of the cognitive pathologies described were similarly exhibited by subjects in the clinical interview study. Many of the students in Marbach’s study couldn’t really explain what a gene or chromosome was. When subjects of the clinical interview were prompted to describe the transfer of traits from parents to offspring, they described it as a flow of information between generations; the awareness of genes or chromosomes was either weak or nonexistent, Amazingly enough, the students in Marbach’s study responded in a comparable manner (Marbach, 184) A similar scenario occurred when Marbach asked students, “What is a gene?” Later in the case study, Marbach observed that “Most of the responses in all four groups were “a gene is a responsible for transferring information.” This is an issue that is constantly examined within the analysis of the clinical interview; it is a real educational blemish that many students use the word gene and trait interchangeably. As discussed above, many don’t understand the different between the two. In conclusion, the group’s final analysis and Marbach’s case study both suggest many students think “a gene is synonymous with a trait”.
- The purpose of this task was to assess students’ understanding of basic principles governing meiosis and the relationship between genes and chromosomes.
- We asked questions such as: “How do parents pass traits to offspring?”, “Do egg and sperm have anything to do with it and what are they specifically?”, “Do offspring get the same number of traits from each parent?” “Do you know what a chromosome is?” and “Do you think there is a relationship between genes and chromosomes?”
Students Understanding of Meiosis
- Overall the subjects recognized that offspring inherit traits from parents in the form of genetic material. There was a general understanding that genes, DNA and chromosomes serve as this genetic material.
- All of the subjects, except for one who was unsure, also agreed that egg and sperm were involved with parents passing on traits to their offspring.
Students Misunderstanding of Meiosis
- The subjects had difficulty with the mechanism behind how parents pass on traits to their offspring. There was a failure to recognize that egg and sperm each carry a single chromosome from each parent which join together to create a diploid offspring with increased genetic variation.
- There was no consensus on the kind of genetic material that parents passed on to their offspring. Genes were primarily discussed in terms of determining traits and DNA as hereditary information, which parallels other research on students’ understanding of genetic concepts (Marbach-Ad, 2001). The subjects did not spontaneously form the connection between DNA, genes and chromosomes. Even when prompted, students had difficulty forming a connection between these concepts. When asked about DNA’s role in the transference of genetic information one subject responded, “Yea, DNA does the same thing; it passes traits to offspring just like genes and chromosomes.”
- Most of the subjects had difficulty putting together the correct relationship between genes and chromosomes. One student thought “chromosomes were the building blocks of genes”, and another one thought that “chromosomes are in genes.” Most of the subjects did not correctly locate genes on chromosomes, which is consistent with research showing that students are unaware of the connection between genes and chromosomes (Lewis and Wood-Robinson , 2000).
- The purpose of Task Three was to determine students’ comprehension of mutation. Questions that made up this task include ones that would reveal understanding of genetic change, such as: “Why is it that we don’t see as many giants and dwarfs in the world as we do normal people?”, “What has to happen in order to make an abnormal person?”, “How does a mutation occur?”, “What would happen if your genes were to change now?”
The student’s prior knowledge of mutation:
- Students certainly understood the connection between mutation and genetic change. For example, one student remarked: “If my genes changed, I would look completely different”
- Students understood that if a gene was to change a mutation could have caused this phenomenon to occur.
- All of the subjects agreed that a mutation could cause an abnormal physical trait to occur.
The students lack of knowledge of Mutation:
- Students were unsure of the various mechanisms underlying the change for mutation to occur. Ex: One of Edgar’s students said: “I don’t think they know how mutations occur otherwise they wouldn’t call them that”.
- The students didn’t understand that changes in physical traits were caused by alterations in the genetic code. They only saw “mutations” in terms of physical traits. While they understood that a genetic mutation could cause a person to become giant –sized, causing an abnormal or “mutated” appearance, they had no idea that the genes responsible for normal growth were also “mutated.” This is because most students conceptualize their physical traits as an entities existing by themselves; most don’t understand the genetic mechanism (genes and chromosomes) that governs the development of such traits.
Implications for Improvement:
- The results examined above are indicative of the fact that current teaching methods in science education need to be improved. While many students leave the K-12 educational system with some semblance of science knowledge, the above results infer that many key concepts in life sciences are not being sincerely conceptualized by today’s student population.
Task One Discrepancies:
- Students understood that genes are transferred from parents to offspring, and that they are responsible for physical traits, but there was not a lot of depth apparent in this understanding. Their comprehension of the connection between genes and traits seemed to suggest ‘rote memorization’ because many students could not differentiate between a ‘gene’ and a ‘trait.’ Their answers did not indicate that they understood that genes are made up of DNA or that DNA encodes for protein. Many students thought proteins had nothing to do with physical traits, disproving the notion that everyone comprehends the central dogma in their high school biology class. These students need to learn that genes aren’t something intangible or something “caught” in the manner of a virus; they are instructional entities that encode for proteins, the functional units behind physical traits.
- The cognitive connection between genes and traits is a good beginning foundation, however, and with better instruction, students like these could easily accommodate correct information into their existing schemas. By reviewing the fact that all humans (except in rare cases) have the same amount of chromosomes (therefore having the same amount of genes) but do not have the same physical characteristics, students may be able to define genes and traits as separate entities. Once these are seen as separate entities, students may wonder how the acquisition of genes results in various traits, and this could lead to a discussion of transcription and translation. Once students’ ideas are made public and discussed, they may become more aware of ‘missing links’ in their conceptual schemas.
Task Two Discrepancies:
- Many of the students interviewed had little or no understanding of the process of meiosis. Aside from the oft repeated mantra that “kids get genes from their parents”, no one could explain the underlying mechanism beyond this transfer of biological information. Some of the students understood that males have the chromosome arrangement XY and that females have the chromosome arrangement XX, but none of them could branch off into discussions about gametes carrying genetic information. To make matters worse, many students confused genes and chromosomes. This body of results demonstrates more problems of rote memorization and indicates that meiosis is a concept that is easily misunderstood by students. To rectify this situation, the distinct definitions of genes and chromosomes must be made evident to students. Students also must comprehend how and why a diploid cell propagates four haploid cells, which can be genetically different from the original cell. Through exercises like scientific inquiry and thoughtful lecturing, students may gain a more sincere appreciation for many facts they have internalized superficially.
Task Three Discrepancies:
- While many students understood that mutations are responsible for causing genetic change, and that mutations could result in abnormal physical traits, their answers did not express a comprehension of a causal relation between genetic abnormalities and trait abnormalities. The results for this task are indicative of a theme that has resounded throughout this entire summary; students view many biological entities such as being abstract or disconnected, and many fail to realize the underlying mechanisms governing ‘visible phenomena.’ In other words, the students were able to see the relationship between having a mutation and having gigantic growth. Yet they could not grasp that the abnormal growth resulted from an alteration in the genetic code, and seemed to think that “a mutation” was something one could “receive” like a gene. These answers are indicative of some serious conceptual confusion. Such cognitive disconnect could first be rectified by explaining that mutations, by definition, are changes in the genetic code. By again reviewing the processes of transcription and translation, students may begin to realize that a missing or incorrect codon results in an incorrect or missing amino acid, ultimately resulting in a weakly functioning or nonfunctioning protein. As stated earlier, more careful instruction may help students internalize more concepts that they are apt to misconstrue.