Everything that makes you who you are is stored in DNA.  Scientists call all of the DNA in one cell of an organism its genome.  The term genome comes from the combination of the words gene and chromosome.  In 1990 researchers created the Human Genome Project to identify the DNA sequence of every gene in the human genome.  This would require them to figure out every gene that belonged to every chromosome and where each was located.  The goal in unraveling all genes was that they would be able to control the actions of specific key genes and, in the future, be able to treat patients with a recognizable combination of genes.  Gene therapy involves inserting copies of a gene directly into a person’s cell.

The knowledge scientists have acquired through studying DNA also led them to try to identify and correct the defects that produce genetic disorders.  Genetic engineering is where genes from one organism are transferred into the DNA of another organism.  For example, cloning is a type of genetic engineering.  A clone is an organism that has exactly the same genes as the organism from which it was produced.  While highly controversial, in 1996, scientists cloned a sheep named Dolly.  Also, a lot of the food sold in stores is genetically engineered.  For example, tomatoes can be engineered to be bigger, stay fresh longer, and all be harvested at the same time.

Another advance in genetics can be seen in selective breeding, which is selecting organisms with desired traits to be parents of the next generation.  This can be achieved through inbreeding, which crosses two individuals with similar characteristics, or through hybridization.  Hybridization is when breeders cross two genetically different individuals in hopes that the offspring will have the best traits from both parents.

Review:

1. What is the Human Genome Project?
2. Explain what it means if something is genetically engineered.
3. What is hybridization?