Does Mendel fit in
contemporary high school curriculum?
By Tuomas Aivelo
It’s not too often one
gets real eureka moments, but I had one of those last August. I participated on
Logical Reasoning in Human Genetics course taught by Ken Weiss, Anne Buchanan and
others in University of Helsinki. I promised to write this up for Mermaid's
Tale (as Anne has been continuously complaining it's difficult to read my own
blog Kaiken takana on loinen via Google Translate).
One of my self-set
objectives for the course was to figure out what kind of curriculum high school
(or as it's called in Nordic context – upper secondary school) biology should
have. Finland is about to update its national core curriculum and I have a soft
spot for genetic education so I have been involved in curriculum design.
The problems with genetics education are well-known: students have poor understanding of what
genes actually are, how genes function and students are not able to perceive
how 'gene' means different things in different fields of biology. Lack of
understanding of scientific models is very pervasive in biology. While our
peers in chemistry and physics education have done better work in explaining
what scientific models are (i.e., “Bohr model”, “Standard model”), we have been
overwhelmed by many different models for ‘gene’.
I remember when I for
the first time understood that gene can actually mean multiple things. It
wasn’t that long ago, probably in the beginning of my PhD studies. I wish
somebody would have earlier told me this explicitly. Suddenly I understood most
of the debates which transcend the fields of biology and involve genes are related
to different meanings of genes in different fields rather than anything based
on reality.
Scientific models are
most of all helpful in making the reality more easily approachable for
scientific inquiry. They are very powerful heuristic tools. The problem lies in
genetic textbooks having several different scientific models of ‘gene’ which
are not explicitly outlined as scientific models. A standard high school
biology textbook can contain several, contradictory, gene models while not
explaining why they are contradictory.
This all should cause
worry as genetics education is actually very important. The most often discussed result
of misconceptions in genetics is genetic determinism. Here I refer to the idea
that traits are fixed by genes as
genetic determinism. Genetic determinism excludes meaningful impact of
environment out from the genotype-to-phenotype relation and it has never been
scientifically sound theory. (Genetic
determinism can also refer to broader idea that genes have an effect on
phenotype. This is obviously widely accepted idea. I’ve suggested the use of
term “hard genetic determinism” to differentiate from “scientific genetic
determinism."
School curriculum,
teachers and textbooks are not the only problem, but also science journalism
is rife with ”gene for” news. “A gene for a trait” is very deterministic view
of gene function. The school should at least equip students with the tools to
assess these news. The real problem lies in genetic determinism being implied
to lead racists views and lack of intestest in personal behaviour in disease
risk. In Logical Reasoning in Human Genetics course, Joseph Terwilliger also
gave a good reason why every geneticist should be worried of genetic
determinism. He attributed the people's worry of genetic privacy (for example,
related to the insurance companies and job applications) to the overselling of genetic determinism: people feel unsafe sharing their genome because they
think a meaningful understanding of them as humans can be simply read from DNA.
Furthermore, this worry could lead to too strict laws which prohibit the use of
samples and lack of consent for genetic studies.
So, the question is:
what should we teach the students? At the moment, genetics education is
dominated by Mendelian genetics. The canonical learning sequence in genetics
starts with Mendel and his peas and works out pea pedigrees and segregation
analysis. One of the central exercises is to figure out from pedigrees which
kind of genotypes and phenotypes individuals have and which probabilities there
are for a given phenotype to be expressed. This approach has been strongly
attacked in last years. For example Michael Dougherty and Rosie Redfield (here and here) have attacked the Mendelian approach in genetics education in high school and
introductory university courses, respectively.
There has also been
defensive effort on the importance of the Mendelian approach. Mike Smith and
Niklas Gericke argued that Mendel's work belongs to the general scientific literacy as it is a central part of our culture. Furthermore, they suggested that the chronological
approach to genetics increases student motivation and understanding of the
nature of the science. They also suggested using Mendel as an example that has
heuristic value as a simple model of inheritance.
I'm not impressed with
these arguments. If we have a culture of learning genetic determinism in school,
purging Mendel from contents would only make it easier to change this culture.
Historical or chronological approaches to different fields of biology are rare:
normally genetics and evolution (e.g., Mendel and Lamarck-Darwin) are the only
ones widely used. Furthemore, it is highly contentious if the Mendelian ”laws
of inheritance” are actually a simple model of inheritance which could be used
for a more detailed view of genetics. Simple, yes, but they work in very limited
context. In fact, in contemporary teaching, while “the historical” aspect is
often included, the contemporary part of the genetics is rather limited. In oursurvey of gene models used in Finnish high school textbooks, we did not find
any modern models:
all the models used were formulated before 1960s. We have an obvious problem: history is taking space from the contemporary understanding of genetics.
This is the point,
when eureka comes to help: it’s not about Mendel or history. It’s not about the
contents. It’s about what we are teaching at a more fundamental level.
Until now, Mendel and
his peas have been used to answer how traits are inherited. In fact, the
current Finnish curriculum notes that the course contents should address “the
laws of inheritance”. The right question, as I see, is how the inheritance of
the traits is studied. Let’s not focus on how inheritance happens but rather
how we can study this phenomenon. Here we are at the heart of one of the
central problems in science education in general. In school, we learn how things are, rather than how we know.
When we present Mendel
as an example of how early inheritance patterns were studied, it brings all the
contentious concepts into the right context. 'Dominance' and 'recessiveness' are
highly useful concepts in the Mendelian context. This approach would bring a
natural possibility to discuss why Mendel used peas for his studies and how
useful these studies are to infer the inheritance patterns of other traits. This
would highlight what differences there are in inheritance of traits in humans
and peas.
Obviously, this
approach would lead to less dominant place of Mendelian inheritance in biology
classes as then Mendel would be only one of the many approaches to study the
inheritance of traits. In any case, it would still make it possible to have a
historical approach or other innovative approaches to the teaching. It allows
for an easy approach to the models in genetics and what they mean without making
Mendelian inheritance the model, but rather one of many models.
The current trend in science education is to put the emphasis on the Nature of Science (e.g., what
science is and how it is done) and socioscientific issues (e.g., how knowledge
of science can be used by active citizens). The question of how things are
studied obviously suits the Nature of Science emphasis nicely and it shouldn't
be too much of a stretch to expect that the understanding of how inheritance is
studied makes it easier to have informed decisions on inheritance.
One of the real
problems in biology education is that the teaching strategies are rarely
studied in classroom context. Only empirical testing can answer if this
emphasis on why more than what and how leads to better learning in genetics.
