Name: Andrew N.
I am currently teaching about
Mendelian genetics, and so many of my students do not see the point of it at
all. How much of it is used today in labs or by genetic counselors? It
seems like it is not considered very important anymore in any high
Maybe this tragic example can stir up your class.
Recently a genetic disease was diagnosed in an adult
male, 45 years old, which leads to brain disorders and is
fatal and untreatable. In the past the man had donated
sperm to a hospital to treat infertile couples--the
standard checks had not detected the disease. From his
sperm, 18 children were born. The discovery of his
disease resulted in an ethical uproar: should the
parents of these children be informed about the risk
they run? It was decided to do so before the children
reached adulthood, so that they would know if they
were carriers. The back side of it: those children
know now that their future is grim, for a disease that
will only present itself at mid-life.
Treat this example in your class. Let them calculate
what % of children were expected to suffer the disease
with if the disease were autosomal/recessive etc. Link
it to the ethical aspects. The example clearly
illustrates how relevant the Mendelian genetics are.
Dr. Trudy Wassenaar
Yikes! I do not know what curriculum you are referring to, but biology is
heading in the direction of molecular biology and away from the traditional
systems/animals/plants approach in a big way. With the advent of the Human
Genome Project, there is so much to know about ourselves and the way we work
at the molecular level that there is not enough time in the year to teach it
all. Consequently I have an entire year course in genetics that I teach.
Look in any high school biology text and look at the number of chapters that
are devoted to genetics and you will see this shift. Mendelian genetics is
interesting to most kids, just because they have questions about how they got
their brown or blue eyes or what the probability is that they can pass on a
genetic disease to their offspring. It is important to understand Mendelian
genetics in order to understand the importance of DNA and important to
understand DNA to appreciate biotechnology issues: cloning, stem cells,
genetically modified food, etc. Kids do not always know what is best for
them-if it were up to them to pick what they wanted to learn they would
usually pick the easiest path. And genetics is definitely not easy.
Mendelian genetics is the basis of all genetics research and discoveries.
Many genetic disorders are listed as being caused by a single gene. See
OMIM, the Online Mendelian Inheritance in Man database, at
http://www.ncbi.nlm.nih.gov/omim/. Understanding the inheritance patterns of
genes is essential as our knowledge of genetics expands. Without a solid
foundation to build our knowledge on, we will not be able to master the
nuances and newly discovered facts, or the new modes of inheritance, such as
As new research takes us into adult diseases and diseases with
multifactorial inheritance, students will need a greater understanding of
multifactorial inheritance and statistical methods. Nevertheless, this will
be in addition to single-gene, or Mendelian, genetics - not instead of.
Sarina M. Kopinsky, MSc, HED, CGC
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Update: June 2012