CTS Guide: Inheritance of Traits, pp 134-135- Section IV Research Summaries
Inheritance of Traits
11 and 12-year-old students have been found to struggle with linking “characteristics that you get from your parents” to inherited genetic information (Cisterna, Williams and Merritt, 2013).
Some students find it more difficult to explain sibling-sibling similarity than parents-offspring similarity (Williams 2012).
When asked to describe how physical traits are passed from parents to offspring, elementary, middle, and high school students all exhibited some degree of misconceptions, including the idea that traits are inherited from only one of the parents and that certain traits come from only the mother or only the father (AAAS 2009).
Difficulty understanding equal contribution of traits from each parent persists into adulthood. In a study of adults (age 18-50), on their understanding of the link between cancer and inheritance, 93% thought that if a son looks like his father than he is more likely to get cancer if his father has it (DeVries et al 2005).
Use of the word dominant in regard to dominant and recessive traits may contribute to several misconceptions. For example, students may think that dominant traits are “stronger” and “overpower” the recessive trait, that dominant traits are more likely to be inherited, that dominated traits are more prevalent in a population, that dominant traits are ‘better,’ and that male or masculine traits are dominant (Donovan 1997).
Some ideas about heredity stem from students’ thinking about the influence of parental characteristics including the commonly held idea that most characteristics are inherited from the mother since she carries the young and that male offspring get their characteristics from the father and female offspring get their characteristics from the mother (Driver et. al, 1994).
Engel Clough and Wood-Robinson (1985) found that some students had a tendency to favor the mother as the primary contributor of inherited traits and held a belief that daughters inherit from mothers and sons inherit from fathers. In some cases, this belief follows students right into adulthood, where it persists.
In a study by Hackling and Treagust (1982), 94% of 15-year-old students understood the concept that one’s traits come from parents, 50% understood that reproduction and inheritance occur together, and 44% understood that one gets a mixture of features from both parents.
In a study of ideas about the mechanism of inheritance among children ages 7–13, Kargbo, Hobbs, and Erickson (1980) found that half the children gave a naturalistic explanation, such as nature makes offspring look like their parents. Some thought traits were decided by the brain or blood. Only a few older children in the sample mentioned any genetic principle. In analyzing the students’ responses, the researchers found that they were not giving flippant, unthought-through answers but rather were drawing on their own conceptual frameworks to make sense of inherited phenomena.
In an older study by Deadman and Kelly (1978) that sampled 52 students ages 11–14, researchers found that boys had a prevalent conception that traits from male parents were stronger in the way they were expressed.
Role of Chromosomes, Genes, Proteins in Traits
Some students do not understand that genes are physically passed down from parents to offspring through DNA. Some think genes skip generations or that they get their genes from non-parental relatives such as aunts or uncles, not realizing that genes come directly from the individual’s parents (Freidenreich, Duncan, and Shea 2011).
A study conducted by the National Institutes of Health on high school students’ essays from a genetics essay contest revealed several genetics misconceptions. One of these is that students believe one gene is always responsible for one trait (Shaw et al. 2008).
Researchers have shown that students have difficulty reasoning across different organization levels in genetics such as genes, proteins, cells, tissues, organs (Duncan and Reiser 2007).
Students sometimes do not differentiate between genes and traits and may use the words synonymously (Lewis and Kattmann 2004).
A study of 16-year-old students in England and Wales showed a poor understanding of the processes by which genetic information is transferred and a lack of basic knowledge about the structures involved. There appeared to be widespread uncertainty and confusion over the use of genetics concepts such as genes and chromosomes (Lewis and Wood-Robinson 2000).
Many secondary students have been found to be unfamiliar with the role of proteins in expressing genetic traits (Marbach-Ad and Stavy 2000).
The commonly used intuitive rule of “more A, more B,” may cause some students to reason that if you have more of one thing, you will have more of another (Stavy and Torosch 2000). For example, students may think if an organism is more complex, then it will have more chromosomes.
Research has shown that students often initially conceive of genes as passive particles that are associated with traits rather than information-carrying entities (Venville and Treagust 1998).
Several studies have found that even before students receive formal instruction in genetics, they know the words gene and, less frequently, chromosome. Students may know these words, but they have little understanding of the nature or function of • genes or chromosomes (Driver et al. 1994).
Meiosis, Punnett squares and Mendelian Genetics
Even though instruction about chromosomes often begins in middle school, for more than 30 years, difficulties in understanding the process of meiosis have been documented (Newman, Catavero, and Wright 2012).
Studies of seventh graders showed they struggled to explain the difference between mitosis and meiosis and how meiosis passed along genetic information from parent to offspring (Williams et al. 2012).
Research has consistently shown that students struggle to understand meiosis and to use the meiotic model to explain patterns observed in genetic crosses (Duncan, Rogat, and Yarden, 2009).
Research indicates that even after being taught, students still hold on to misconceptions about meiosis (Lewis and Wood-Robinson 2000).
Students’ difficulties in understanding processes of cell division like mitosis and meiosis, experience may stem from their inability to differentiate between replication, pairing, and separating as well as deciding whether these processes occur in mitosis, meiosis, or both (Smith 1991).
The standard use of Punnett squares to solve Mendelian genetics problems contributes to students’ misunderstandings of phenotypes and the complexities of the mechanism of inheritance (Moll and Allen 1987).
Aquired Traits and Influence of Environment
An organism’s characteristics are affected by genetic information in cells and by the organism’s lifestyle and environment, but research indicates that most students at secondary school level think of genes as the only determinants of an organism’s characteristics (Jamieson and Raddick 2017).
Students up to age 11 often believe that acquired characteristics (resulting from interaction with the environment or from learning) can be passed from parents to offspring (Allen 2014).
Researchers have found that 11 and 12-year-old students can usually distinguish between, and provide examples of, characteristics that are inherited from their parents and characteristics that are caused by interactions with their environment (Cisterna, Williams and Merritt, 2013).
Mutation
An analysis of high school student essays about genetics revealed a common misconception that one gene with one mutation always causes disease (Shaw et al. 2008).
Genetic Engineering
An analysis of research carried out across many countries showed that most secondary students lack knowledge about genetic engineering, even in countries that produce genetically modified organisms nationally and that their attitudes toward genetic engineering were mostly negative (Purbosari and Astuti 2023).
A study by Fernbach (2019) showed that the less objective knowledge people had about science and genetics the more negative their attitude toward genetic engineering and products like genetically engineered foods.
A study by Vera and Vera (2014) found tha Czech female students had less knowledge of genetic engineering than males. Overall, both male and female students tend to have a negative attitude toward genetic engineering.