The Genetic Origins of DiseaseBio paper topics on genes often make up the bulk of any students' biology class. Whether your students have an idea of the workings of jeans or they're still trying to learn, it's a good idea to guide them through the genealogy of humans and how genes were passed from generation to generation.
The Human Genome Project was initiated in the mid-1990s by the National Institutes of Health to map the human genome. Genes and their physical makeup are the basis for all the traits that we find fascinating and which distinguish us from our nearest living relatives. Just as the human brain is composed of millions of neurons, each of which performs a specific function, so too are genes a computer program that directs, for example, a type of skin cell to produce an enzyme to attack a virus.
Gene sequences from animals and plants are now part of the research carried out to understand the mechanisms underlying developmental and reproductive processes, and this has led to insights into human development. How genes are passed from parent to offspring is one of the biggest unanswered questions in genetics, and how DNA is expressed and regulated by the environment is key to understanding the causes of disease.
Early efforts to map genes involved in the painstaking task of breeding animals and plants with each other and trying to track the changes that resulted from the mutations that occurred during cross-breeding, but the Human Genome Project took the next step of designing the first modern genome sequencer. Through this technology, researchers have been able to determine many of the variations and differences that exist within the genomes of people and their ancestors.
Much of what we know about gene variations is based on the family trees that researchers can compile. Individuals who share a common ancestor for two or more generations (called inbreeding depression) are more likely to share the same gene variant than those whose families have no known shared ancestors. These gene variants are also found in people with diseases such as cancer, Parkinson's disease, and Huntington's disease.
Because these gene variants are found throughout the population, it makes sense that there would be many events in which an individual would be 'caught' by such a gene variant and then passed on to the next generation. Studies of genomics and its interaction with human health problems have shown that there is a genetic component to everything from asthma to colon cancer, and that the same gene variant can result in differences in susceptibility depending on the context in which it appears.
For example, asthma is more prevalent in men than in women because the genes that code for the proteins that form asthma receptors in the body are more likely to be located on the X chromosome. Although all men inherit a Y chromosome that has its own set of genes, studies show that men with asthma tend to carry only one copy of this chromosome, and that the number of copies that they carry could make a difference to their susceptibility to the disease.
Understanding the basics of gene variants and how they interact with the environment to create disease is the first step toward developing personalized medicine, so that doctors can devise treatments tailored to the individual. What students in school learn about genes as a part of their science curriculum should be taught to students in biology classes to help them understand the genetics of disease.