|
||||||||
 |
||||||||
|
Introduction to genetics research These are exciting times for human genetics research. The Human Genome Project, initiated in 1985, has aided our knowledge about our DNA and our genetic code. However, knowing the genetic code is only a small part of the puzzle. A great deal of research still needs to be done to learn what the code means, how it works, and how changes in the genetic code can cause health problems or birth defects. First, a quick genetics lesson to understand more about our approach to genetics research. Our genetic code is contained in our DNA, which is packaged into structures called chromosomes. We all have 46 chromosomes in each of our cells, the same 46 chromosomes in each cell of our bodies. Therefore, each of our cells has exactly the same genetic code as every other cell. The DNA is made up of building blocks referred to as nucleotide bases. There are 4 different nucleotide bases - adenine (A), guanine (G), thymine (T), and cytosine (C). There are billions of these nucleotide bases within our DNA. It is the order of these bases within the DNA that is our genetic code. Each gene is made up of several thousand nucleotide bases. The Human Genome Project has helped us to learn what the order, or sequence, of these nucleotide bases should be within the genes, but it does not tell us what each of these genes does within our bodies. Nor does it tell us what will happen if there is a change (mutation) in the number of nucleotide bases or the sequence of nucleotide bases within a gene. It also does not tell us which genes might be altered in individuals with a particular genetic disorder. In our research laboratory, we are searching for genes which, when altered, are responsible for abnormalities in brain development. In order to do this, we need DNA samples from families with both affected and unaffected individuals. By comparing the nucleotide sequences in the DNA of unaffected family members with the nucleotide sequences in the DNA of affected family members, we can detect subtle differences. These differences may be the mutations responsible for the genetic disorders. Since there are millions of nucleotide bases within our DNA, finding those that may be changed is a slow, laborious process. It is most effective when we are able to test the DNA of several different families all with the same genetic disorder or one large family with many affected individuals. Timeline Genetics research is unpredictable. We may locate a gene responsible for a genetic disorder very quickly or it may take many years. We may also search for years without ever finding what we are looking for. There are several factors which may determine how quickly the research proceeds: How many individuals with the same genetic condition are enrolled in the study (the more, the better), whether or not we have any "clues" to help show us where to look for a gene (such as rearrangements in the chromosomes), and luck. Expectations for families and research participants We hope that our research will help us to locate and identify genes that may cause or contribute to genetic disorders. If we do find such a gene, we then research how this gene functions within the brain to learn more about normal and abnormal brain development. We also search for specific mutations within the gene that are responsible for the disorder in each family. Often, there is a different mutation in the gene in each family studied. If a mutation is identified, this confirms the diagnosis for the family and allows the possibility of carrier testing for unaffected family members. It may also allow the possibility of prenatal testing for "at risk" couples. Most families who participate in research are hoping that our research will yield results which will allow them the option of this testing and will confirm their diagnosis. However, it is important to note that we cannot promise that our research will yield results in a timeframe that is useful to families. Our laboratory has identified several genes associated with various abnormalities of brain development. This could not have happened without the generous participation of the many families who have donated their DNA and medical information for our research. We are indebted to all those who have and who continue to participate. |
||||||||
