There are about __________ known diseases linked to ________________ and scientists are able to diagnose more than ________ of them. A genetic disease is caused by a defect in a person's ____________. Such a defect may result from a ____________ or it may be due to __________ or ______________ genes or chromosomes. Researchers identify genetic diseases by a process called genetic _________________. A picture of a cell's chromosomes is called a _________________.
A technique called ________ _____________________ allows scientists to replace ___________ genes with _____________ ones. One method uses an altered __________________. A ______________ normally attacks cells by attaching to the cell's outer ___________________ and pushing its own _________ into the cell. The viral ___________ uses the host cell to make copies of _____________. In an altered virus, scientists splice a ______________ gene into the viral ______________, then let the virus transfer the ___________ into the patient's cells (see Fig. 4.13, pg. 122).Gene therapy with _________________ cells can help a patient with an __________________ disease. But to avoid passing on the genetic disease to offspring, the defective _____________ would need to be located and altered in a patient's __________________ cells.
All of the genes found in a complete set of chromosomes make up a _______________. The mapping of the entire human genome began in 1990 and was completed in 2001 and is called the _____________ ______________ __________________. An alternative to replacing faulty genes in humans is to engineer ____________________ to produce the _________________ of the gene. People with _________________ cannot produce their own insulin (a ________________ that regulates blood _________________). Diabetics used to be given insulin taken from ______________ or _______________. In 1978, the gene for making insulin was transfered to ______________________, which then produce the insulin for human use. Other substances made this way are: __________ ___________________ hormone and ______________________.Animals, as well as ___________________, can be given human genes. Genetically ______________________ or __________________ animals are produced by adding human genes to the _______________ _________________ of the parents. The offspring grow up with a ________________________ gene. Usually the gene product is a _________________ that can be collected in the animal's ____________________ and then purified. Some examples are: human _______________________ (source of iron) and human __________________ _____ (to treat blood clots). An advantage of using mammals is that the proteins can be collected in the animal's ___________________ and the animal does not have to be ____________________.