The latest advances in genetics have begun to unsettle the science behind many of the common examples of genetic inheritance biology teachers have been using for decades.  Simple inheritance of characteristics controlled by single genes really does occur.  One example is cystic fibrosis.  However as we learn more about genetics, and epigenetics simple inhertance of this kind is becoming a less popular explanation for many characteristics.  Is this the beginning of a paradigm shift in Mendelian genetics? 

The list of visible phenotypes that are not controlled by a single gene with two alleles is getting longer.  If we use these example in class we are teaching genetics which is incorrect.

• Attached earlobe
• Bent pinkie
• Cheek dimples
• Cleft chin
• Eye color
• Hair color
• Hitchhiker's thumb
• Mid-digital hair
• PTC tasting
• Toe length
• Tongue rolling
• Widow's peak

Some geneticists even go so far as to say, "It is an embarrassment to the field of biology education that textbooks and lab manuals continue to perpetuate these myths."  The solution is not so easy.  Using the characteristics of farm animals or pets might be a good solution, but I bet these traits will become equally incorrect in the course of time.  Safest may be those known biochemical variations, known to be caused by single genes; blood groups and cystic fbrosis. The advantage of these is that they are likely to be examples used in future IB exam questions.

A quick reference to inherited human traits, which outlines some recent discoveries which cast doubt on single gene inheritance of nearly all visible human traits.

Information and a video from the Council for Responsible Genetics, contains incisive, succinct articles by leading scientists disputing the exaggerations and misrepresentations of the power of genes that circulate in both popular media and scholarly journals.

More detail and some references to explain what the latest thinking is about the genetics of human traits in a website called the Myths of Human Genetics