The DNA is broken down into bits and is tightly wound into coils, which are called chromosomes; human beings have 23 pairs of chromosomes. These chromosomes are further broken down into smaller pieces of code called Genes. The 23 pairs of chromosomes consist of about 70, genes and every gene has its own function. As I have mentioned earlier, DNA is made up of four nucleotide bases, finding out the arrangement of the bases is called DNA sequencing, there are various methods for sequencing a DNA, it is usually carried out by a machine or by running the DNA sample over a gel otherwise called gel electrophoresis.
Fig 1. Sample genetic code with complementary strands. Determining the gene's functionality and position of the gene in the chromosome is called gene mapping. Recent developments show that scientists are mapping every gene in the human body. They named their project Human Genome Project HGP , which involves careful study of all the 70, genes in human body. That's some thing unimaginable. See Subscription Options.
Discover World-Changing Science. Stuart E. Ravnik, assistant professor of cell biology and biochemistry at the Texas Tech University Health Sciences Center, summarizes the answer to this seemingly simple question: Image: Nikolaj Blom and Michael Lappe.
Get smart. Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? Create Account See Subscription Options. Continue reading with a Scientific American subscription. Some have long fur and others have short fur. Dalmatians have genes for white fur and black spots, and toy poodles have genes that make them small with curly fur. You get the idea! Scientists are very busy studying genes. They want to know which proteins each gene makes and what those proteins do.
They also want to know what illnesses are caused by genes that don't work right. Genes that have been changed are called mutations. Researchers think that mutations may be partly to blame for lung problems, cancer, and many other illnesses. Other illnesses and health problems happen when there are missing genes or extra parts of genes or chromosomes.
Some of these gene problems can be inherited from a parent. For example, take the gene that helps the body make hemoglobin say: HEE-muh-glow-bin. Hemoglobin is an important protein needed for red blood cells to carry oxygen throughout the body. If parents pass on altered hemoglobin genes to their child, the child might only be able to make a type of hemoglobin that doesn't work properly.
This can cause a condition known as anemia say: uh-NEE-mee-uh , a condition in which a person has fewer healthy red blood cells. Sickle cell anemia is one kind of anemia that is passed on through genes from parents to children. Parents with a changed CF gene can pass it on to their kids. People who have CF often have trouble breathing because their bodies make a lot of mucus say: MYOO-kus — the slimy stuff that comes out of your nose when you're sick — that gets stuck in the lungs.
People with CF need treatment throughout their lives to keep their lungs as healthy as possible. Gene therapy is a new kind of medicine — so new that scientists are still doing experiments to see if it works. It uses the technology of genetic engineering to treat a disease caused by a gene that has changed in some way. One method being tested is replacing sick genes with healthy ones. Gene therapy trials — where the research is tested on people — and other research may lead to new ways to treat or even prevent many diseases.
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