How many people do you know with a purebred St. Bernard. Maybe none, maybe quite a few. What does purebred mean? Purebred or pure breeding means that an animal or plant has certain traits that it has gotten from its ancestors which may be passed on to its offspring. The possibility is what ranchers, animal breeders, and horticulturists (people who breed plants) are interested in. An example of this is purebred Hereford cattle. These cattle have two genetic disorders that have plagued them over the years. In the early 1900's dwarfism was a major problem for Hereford cattle. Dwarfism is a hidden (recessive) trait. If another gene is present, the organism won't show the hidden (recessive) trait. If two non-dwarf animals with the hidden trait are bred they might have dwarf offspring.

Hereford cattle have another genetic disorder. Some cattle are born with curly hair. This usually isn't a problem. The problem occurs when two cattle with curly hair are bred ... they have offspring that are hairless. While the animal is not completely hairless like a hairless cat or hairless mouse, you can sure tell that they have bald areas on their skin. In a cold climate like most of Utah, cattle who are partly bald will not survive winters well. In warm climates like southern Utah, cattle that are partly bald have a problem with sunburn.

You will now have a chance to look at traits in people. The goal of this activity is to survey relatives. Relatives can include: parents, grandparents, brothers or sisters, cousins, uncles, and aunts. You should also include two non-relatives to compare with your own family. You will also have a chance to compare your survey with other students in class.

If you are in a blended family or for another reason can't collect data on your biological relatives, write a short explanation about what data you are missing. If you wish, you may use a friend's family for data.