This interdisciplinary set of mini-units on basic human genetics is designed to be taught during the course of a school year as a theme of focus for integrating curriculum in a self-contained sixth grade class where one teacher is responsible for all curriculum areas. Alternatively the various components of the unit could be shared by single-discipline teachers working with the same groups of students.
The introduction to the unit, “Similarities and Differences,” may begin early in the school year. It can be developed over a period of time as the mathematical skills needed to carry out the activities are taught. The balance of the mini-units are intended to enrich the life sciences normally covered in the curriculum. Much of the teaching will, of course, take place in science classes. However, an extensive student bibliography is provided so that reading and report writing activities can be assigned. Social studies content includes career exploration and current event interest.
I intend to use the unit intermittently during the year as a continuing theme. However, the mini-units adapt readily to being taught separately as interest and need dictate.
Mass media reporting of advances in the field of genetics has become an almost daily occurrence. In one recent week, national television news shows were announcing a probable genetic link to alcoholism and another to the susceptibility to tuberculosis.
The New Haven Register
highlighted a Yale study to “target genetic flaws . . . before a woman is even pregnant”.
My Weekly Reader
reported the genes from firefly-like beetles being placed in bacteria.
The resultant glowing bacteria are being used to study patterns of inheritance. A recent advertisement appearing in
offered genetic “fingerprinting” of children as a means of positive identification in cases of kidnapping. The current interest in the topic takes human genetics out of the realm of advanced biology classes in high school and college and places it with a background of general knowledge necessary to comprehend reading and current events.
Human genetics is, above all, the study of human diversity. There are, of course, those common traits that define human beings as a species; but, the variations that occur within those parameters are innumerable. A class photograph of any sixth grade class would certainly point out a wide variety of physical characteristics within the group.
The variety of development found in any group of eleven to thirteen year olds is probably wider than at any other age. As children are entering adolescence, their own rapidly changing bodies and different rates of growth they observe in their classmates causes them to question their own normalcy. Investigating these similarities and differences and exploring the causes of individuality should be a high interest introduction to the unit.
Most science books in use today cover reproduction of plants and animals. This unit reviews sexual reproduction from a genetic point of view, with emphasis placed on the genetic material passed from each parent to the offspring. Although the scientific explanations are simplified to serve only as an introduction to the topic, the exchange and restructuring of the chromosomes within each parent prior to the production of the sex cells is explained. The role of the chromosomes and structure of DNA are introduced. The continuing role of the genes (within the chromosomes) in life-long development, and patterns of inheritance are explored. The usefulness of genetic technology is illustrated by citing applied examples of genetic engineering and introducing the role of the genetic counselor. Other careers in the science of genetics are introduced.
Many of the principles covered in the unit are ideal vehicles for practicing mathematical concepts taught in the sixth grade. The structure of DNA and the pairing of the chromosomes can be illustrated with lessons in symmetry. The frequency of the mirror-image relationship of two halves of living things was cited by Dr. James Watson in
The Double Helix
, his personal account of the discovery of the structure of the DNA molecule.
Practice in measuring and recording the attributes of simple geometric figures introduces children to the scientific practice of writing detailed descriptions to record observations before they begin the more complex task of observing and recording human physical characteristics. Metric tape measures are later used to gather physical data on students; with subsequent recording, graphing, establishing ranges and determining averages.
In studying patterns of inheritance, probability and ratios come into use. The mathematics activities should be planned as group endeavors to accommodate the wide range of abilities found in most classes.