From Mendel's Peas to Genetic Engineering

We can find genetic information from a drop of blood, a sliver of skin or a root of hair The nucleus of the cell which houses the chromosomes that contain the DNA and that can be used to produce a genetic fingerprinting

Gregor Mendel came up with the theory to study how certain features of the plant were inherited.

1. A dominant characteristic will mask the recessive one
2. Genes exist in different forms called alleles
3. An example is the gene for blossom color in many species of flower-a single gene controls the color of the petals, but there may be several different versions (or alleles) of the gene. One version might result in red petals, while another might result in white petals. The resulting color of an individual flower will depend on which two alleles it possesses for the gene and how the two interact. .
4. Chromosomes contain genes, which are responsible for the inheritance of features
5. Humans have 46 chromosomes in most of their cells. However, the egg and the sperms have only 23 chromosomes each. When the egg and the sperm fuse, embryo therefore has 46 chromosomes.
6. Human suffer from many diseases. Some of these diseases such as cystic fibrosis and sickle cell anemia are caused by genetic defects. The genetic material is somehow damaged or altered, and this causes the disease.
7. Most genetic diseases are caused by recessive alleles
8. Tay-Sachs disease is a genetic disorder. Babies born with this disease appear normal at birth and they die at about 3 years old.

There are a few diseases caused by dominant alleles, two examples are Achondroplasia and Huntington's disease. Achondroplasia causes the bones not to grow properly resulting in a stunted body. The Huntington's disease affects the nerve cells in the brain and gets progressively worse. These symptoms include loss of muscle control, depression and memory loss.

1. Studies showed chromosomes were made of DNA and protein
2. DNA looks like a twisted ladder and the sides of the ladder are made up of alternating sugar and phosphates
3. Now, scientists understood the structure of DNA, they could work out how the information carried by the DNA could be copied. They also found out how the DNA instructed the cell to make proteins and how the DNA differed between species.
4. Enzymes can copy a strand of DNA using the Polymerase Chain Reaction (PCR)
5. The whole process of PCR takes 1-3 minute and in 45 minutes, millions of copies can be produced. However the sample cannot have other DNAs, as it would also be duplicated. This is especially important in forensic laboratories where the evidence produced maybe used to convict someone in court of a crime.
6. Some people believed that Abraham Lincoln suffered from a genetic disease called Marfan's syndrome. This disease wakens the tissue that connects different parts of the body. This can cause the person to develop long limbs, thin body and an unusually shaped chest. Lincoln had all three symptoms. However as he died in 1865, nobody can be sure.
7. The technicians laboratory in MIT are working on mapping genomes. A genome is an organism total genetic material.
8. The human genome project started in the 1980s and governments from the world fund it
9. Celera Genomics use supercomputers to put together all the sequences from tiny DNA fragments and they enable to company to human genome map in about a year
10. Human chromosomes are numbered from 1 to 23 and chromosome 1 (2968). The Y chromosome (the male sex chromosome) has the fewest (231).
11. Chopping up the DNA using restriction enzymes produced genetic fingerprinting. The fragments were separated using gel electrophoresis. They were labeled with radioactive markers. A photographic technique was then used to record the position of the radioactive markers.
12. Genetic fingerprinting can be used to identify people, establish family trees and proving parentage and researching genetic diseases
13. A national DNA database could be used to help plan health programs and identify criminals. However this information could be used in a wrong way by commercial companies or even by governments. There would have to be strict controls on who had access to the data and how it was used. For example, banks and insurance companies might use the information about a person's risk of disease to refuse them insurance cover or loans.
14. Gene therapy involves inserting a length of DNA to replace the faulty DNA
15. Scientists also investigating the use of switching off genes in order to treat Huntington's disease. In 2003, Dr Beverley Davison, of Iowa University stopped a progressive brain disease in mice by using a genetic technique called RNA interference. This blocks the RNA produced by the faulty DNA, shutting down the faulty gene.
16. DNA sequences are linked to common heart health problems, such as heart and lung disease, diabetes, arthritis, and many cancers. This knowledge may lead to the development of effective new genes therapies.
17. Genetic engineering means cutting out lengths of one organism and pasting on another. In the last 30 years, many genetically engineered organisms have been produced in order to manufacture foods and medicine.