Our analysis is based on the premise that the discipline of genetics/genomics (and scientific disciplines, in general) is structured around an intellectual core of fundamental concepts. The dynamic nature of science has accustomed us to expect that our understanding of scientific details will change even as further research serves to strengthen the concepts at the core. Such is the case with genetics, where concepts such as the allelic nature of genes, basic processes of gene expression, mutations, genetic variation, and patterns of inheritance have been expanded and enhanced across more than a century. Other concepts, while less familiar, such as differential gene expression and the genetic basis of complex traits, have been recognized for decades as crucial, but only in the past 10–20 yr have advances in technology enabled researchers to elucidate the genetic mechanisms by which they occur.
The collection of concepts that make up our core genetics benchmarks is not definitive. Other groups (several of which are referenced in Methods) have developed their own lists for their own purposes. The ASHG list drew heavily from those previously published lists, but our choices were guided by the specific goal of capturing the minimum number of concepts, at the appropriate level of specificity, that the authors and ASHG's Information and Education Committee believe to be essential for genetic literacy and thus should be understood by all high school graduates. As with all such lists, our process necessitated choosing among concepts that should be included and concepts that should be omitted, and some readers may disagree with these choices. We believe that ASHG, a large and influential professional society in genetics, can make a contribution to the discussion of standards with its views on what constitutes a reasonably specific, comprehensive, and age-appropriate set of concepts in one of the major subdisciplines of biology. Consequently, our choices reflect a moderate level of specificity, and our benchmark list includes 19 concepts rather than, for example, 6 or 60. This acknowledges dramatic changes in genetics over the past two decades, such as the discipline's increasing impact on medicine and direct-to-consumer genetic testing, and the fact that an understanding of additional concepts is needed to raise the standard of scientific literacy among the nation's population. The new concepts we propose can be taught using many different subconcepts and examples, which we do not prescribe.
Overall, our analysis identifies substantial deficiencies in the treatment of genetics in state standards across the United States. Of ASHG's 19 benchmark concepts, 14 were treated inadequately (averaged across all states, including the District of Columbia), and 39 states had Adequate coverage of fewer than 11 concepts (Table and Figure ). Two concepts (continuous variation of complex traits and polygenic inheritance) were virtually absent from state standards. Three of five major categories of genetics concepts are covered inadequately in standards. Only evolution and the nature of the genetic material were adequately covered, while the broad categories of gene expression and regulation and genetic variation were not.
It is particularly troubling that the Inadequate and Not addressed/absent concepts represent ideas that are increasingly important as genetics/genomics matures and assumes practical importance in people's lives. As DNA sequencing and genotyping technologies have become more powerful and less expensive (at rates that vastly exceed Moore's law in computing), they have been applied more often in medical research. It is now possible to investigate the genetic contributions to virtually any disease or normal trait, and our ability to apply knowledge of individual genetic variation to clinical treatment and outcomes is advancing. Even now “personalized medicine” is becoming manifest. For example, roughly 10% of drugs approved by the Food and Drug Administration have labels with pharmacogenomics information, and genetic testing has already become common for certain conditions, such as breast cancer (Hamburg and Collins, 2010
). As Lanie et al.
have written, “Even if people grasp and understand these basic concepts [Mendelian genetic concepts], the impact of this knowledge will be limited. . . it will not go far in helping the layperson understand the barrage of genetic information to which they are exposed through the media—the vast majority of which deals with complex diseases and traits” (2004). Without adequate standards dealing with mutations, gene regulation, and non-Mendelian patterns of inheritance, such concepts may never make it into curricula and assessments.
The most-neglected concepts also demand higher orders of thinking than concepts that tended to be covered adequately. For example, unlike the nature of the genetic material (i.e., DNA), which deals largely with descriptive biology, gene expression (concept 8) deals with the mechanisms of how genes operate and the functional consequences of those operations. The latter involve understanding positive and negative feedback (general ideas that also extend to engineering, computing, and economics) and require thinking at levels of application, interpretation, and analysis. In parallel with being poorly represented in state standards (Table ), assessment questions related to the concepts of gene expression (concept 8) and differential gene expression (concepts 9 and 10) elicited very few responses indicative of complete understan ding by grade 12 students on the 2000 NAEP (2006
; Table ).
Students’ responses to genetics questions on the 2000 NAEP (grade 12) indicate poor understanding of essential genetics concepts
Another specific area of weakness is the state standards’ treatment of mutations. Frequently, state standards do not distinguish between germline and somatic mutations and their connections to hereditary versus nonhereditary genetic disease (concepts 14 and 16, respectively). Failure to make this distinction may contribute to students’ conflating inherited disease with any disease influenced by genetics, a frequent student misconception (Shaw et al., 2008
). Students’ poor understanding of these concepts is also reflected in their responses to a related question on the NAEP (Table ).
There are some bright spots. Perhaps not surprisingly, DNA as the genetic material (concept 1) is well covered by most states, as it should be nearly 60 yr after the elucidation of DNA's structure (average score of 1.7, Table ). The organization of genetic information in the form of genes carried by chromosomes also fared well (1.5). Evolution by natural selection (concept 18) tied for best average score (1.7), and was supported by strong coverage of genetic and phenotypic variation as the substrate for evolution (concept 17; 1.5). These findings support earlier research indicating improvements in state standards’ coverage of evolution (Mead and Mates, 2009
). Unfortunately, state standards are not doing as well framing the population-level and generational timescale at which evolution operates (concept 19).
Learning goals related to single-gene inheritance patterns (i.e., Mendelian inheritance, concept 5) are also adequately addressed nationwide in the state standards (average score 1.5), an encouraging but not unexpected finding. Instruction about genes, alleles, and Mendelian segregation, including meiosis, is virtually ubiquitous in high school general biology, and these concepts continue to dominate instruction in equivalent undergraduate courses (Hott et al., 2002
). These concepts also lend themselves easily to problem-based learning, which engages higher-level critical thinking. Unfortunately, there may be a downside to all this attention. In the context of the modern discipline's broader view of genetics, we may be skewing students’ understanding of the genotype–phenotype connection (Dougherty, 2009
). In essence, if we spend too much time on single-gene inheritance—at the expense of polygenic inheritance and complex traits—then we not only fail to convey modern genetics accurately, but we also risk giving students a false impression that most traits are inherited in the “simple” manner conveyed by the rare single-gene traits that are so often used as examples, such as cystic fibrosis and hemophilia. In fact, patterns-of-inheritance misconceptions represent the second most problematic conceptual category in genetics identified by Shaw et al. (2008)
. Not surprisingly, low scores for concepts related to complex traits and multifactorial causation (concepts 6, 7, and 11) contributed substantially to low average scores for most states.
To get some sense of how our specific results compared with the quality of state science standards as judged more generally, we compared them with the results of an evaluation conducted by the Thomas B. Fordham Institute (Table , columns three and four). Differences in methodology prevent direct comparison; however, weaknesses in state standards are apparent in both analyses.
Our study was limited in several ways. First, states were not scored blindly, which may have allowed some unintentional reviewer bias, although our method of using multiple reviewers and dropping the high and low scores for states with five or six reviewers should have helped minimize such bias. Second, for a small number of states, it is possible that some concepts may have been addressed only at lower grade levels, in which case this analysis would have missed them. The decision to focus exclusively on high school standards was based on a preliminary analysis that indicated that middle school standards were generally repeated in the high school standards for the states that included genetics concepts at both levels. The repetition of genetics concepts in middle and high school standards, in the cases where we observed it, bolsters the argument by Schmidt et al. (2005)
and Daro et al. (2010)
that the current U.S. curriculum does not achieve much depth in math and science. Third, our analysis represents a temporal slice through state genetics standards. Different states have different revision schedules (and processes) for their standards, and the performance of any given state with respect to genetics (or any other content) would be expected to change over time. Finally, our analysis considers only one variable (i.e., standards) in the complex system that constitutes genetics education.
Of course, the absence of concepts in a state's standards does not mean that those concepts will not be taught. Knowledgeable teachers can address such concepts even in situations where high-stakes exams do not require them. However, given the pressures of performing well on state exams and limited classroom time, teachers often prioritize the content specified by their states. Conversely, the fact that concepts are represented in a state's standards does not guarantee that students will learn them (Schmidt et al., 2005
). For example, DNA as the genetic material and the nature of genes were the best-covered concepts for any category on our benchmark list (concepts 1 and 2, Table ); however, only a minority of students gave complete or essential answers to a question dealing with these ideas on the 2000 NAEP. Those concepts have been taught since long before standards achieved their current prominence in education, and yet student understanding lags. Thus, we recognize that improved standards are no panacea.
The fact that 44 states (86%) had genetics standards judged to be Inadequate and only 12 states (24%) had 11 or more individual concepts judged to be Adequate convincingly demonstrates (in our view) a need for improvement when states revise their life sciences standards. ASHG will encourage members of its Genetics Education Outreach Network to volunteer to assist with revisions in those states that allow such participation. Similar networks exist at other scientific professional societies and may offer a generalizable mechanism for involving scientists who are content experts, as well as knowledgeable about K–12 education, in both the evaluation and improvement of content coverage in state standards.
Standards are just one element of what should be an integrated and coherent teaching system, and changes to standards should be made only with full recognition of the effects those changes may have on other parts of the system. Crowded curricula, teacher professional development, and available instruction time, must all be taken into consideration. Within genetics, new conceptual frameworks may be necessary. For example, it may be possible to refocus instruction around complex traits, which have a greater capacity for carrying modern understandings of genetics (as well as traditional ones) than do the simpler, single-gene traits that are used so widely in high school classrooms now (Dougherty, 2009
The NRC's move to generate common science standards offers a different leverage point for modernizing the genetics curriculum. A recent report supports the establishment of clear and common standards across states, noting that roughly one-half the teachers in all states agreed that the standards of their own states were not clear enough, and that 85% think “having tougher academic standards would make at least a moderate impact on improving academic achievement” (Scholastic and Bill and Melinda Gates Foundation, 2010
). Sound science instruction requires expertise in teaching (content knowledge and pedagogy), exemplary curricula, strong assessment, and a supportive system (e.g., administration, professional development). In the current U.S. system, standards are the foundation upon which curricula and instruction are built, and our work shows that the foundation, at least in genetics, is in need of repair. We propose that the findings detailed in this paper are well positioned to guide the development of common core standards in science.