An Austrian monk named Gregor Mendel first saw inherited patterns in pea plants. He experimented with pea plants in the 1860s. One of the things, or traits, Mendel studied was what makes some pea plants tall and some short. He said that the traits must come from units of heredity passed from the parent plants. These units were later called genes.
In the mid-1900s, scientists discovered that genes are made of DNA. In the 1970s, scientists learned how to change DNA with genetic engineering. Scientists also learned that problems with certain genes cause diseases.
Gregor Mendel (1822-1884), Austrian monk, whose experimental work became the basis of modern hereditary theory.
Genes are composed of segments of (DNA) , a molecule that forms the long, threadlike structures called chromosomes . Like chromosomes, genes typically occur in pairs. A gene found on one chromosome in a pair usually has the same locus as another gene in the other chromosome of the pair, and these two genes are called alleles . Alleles are alternate forms of the same gene. Structure of genes
Gene therapy may someday be able to cure hereditary diseases, such as hemophilia and cystic fibrosis, which are caused by missing or defective genes. In one type of gene therapy, genetically engineered viruses are used to insert new, functioning genes into the cells of people who are unable to produce certain hormones or proteins necessary for the body to function normally.
Currently, there are no permanent cures for genetic disorders, but many treatments are available. A procedure called Gene Therapy is on the horizon; it may eventually provide permanent cures for at least some genetic disorders.
In somatic-cell therapy , gene surgeons attempt to fix genetic malfunctions in somatic (body) cells, such as blood cells and skin cells.
In germ-line therapy , genetic alterations are made to germ cells, such as sperm and eggs, in order to treat inherited diseases. Germ-line therapy is highly controversial because such changes would alter the genetic endowment of the unborn and could be passed on to future generations.
The most common technique is to attach healthy genes to genetically modified viruses . These infectious agents, known as vectors, carry the genes into a cell’s nucleus and incorporate them into the genetic material of the infected cell. Another gene-delivery method still under development is Chimeraplasty , in which segments of DNA are inserted into a cell’s nucleus. The DNA segment binds with a defective gene in a way that helps the cell’s repair mechanisms identify and fix the defective gene.
Genetic Engineering, alteration of an organism's genetic, or hereditary, material to eliminate undesirable characteristics or to produce desirable new ones. Genetic engineering is used to increase plant and animal food production; to help dispose of industrial wastes; and to diagnose disease, improve medical treatment, and produce vaccines and other useful drugs. Included in genetic engineering techniques are the selective breeding of plants and animals, hybridization (reproduction between different strains or species), and recombinant deoxyribonucleic acid (DNA).
The Human Genome Project is the most ambitious project in the history of biology. The program’s challenging goal was to identify and sequence all of the DNA in human chromosomes. The project was initiated in 1990 in the United States with government funding, and it rapidly grew into an international consortium of academic centers and drug companies in China, France, Germany, Japan, the United Kingdom, and the United States. The consortium initially hoped to reach its goal by the year 2005.
Using gel electrophoresis scientists can create a map that shows the arrangement of genes within a cell. By comparing the genetic makeup of different species, researchers can determine how they are related.
Genetic Counseling, medical specialty that helps parents and prospective parents evaluate and cope with their risk of passing hereditary disorders to their children. Genetic counseling also helps individuals assess the possibility that they will get a medical condition known or suspected to have a genetic basis, such as Huntington’s disease, breast cancer, or Alzheimer’s disease.
Who benefits from genetic counseling?
1. Prospective Parents.
2. People with a Family History of Disease.
3. Ethnic Groups at Higher Risk for Disease.
Done by: Mustafa T. Dawood. Miss. Lama Berajeckly.