The first in-depth study of genetics was done by Charles Darwin in the mid 1800s. Since then we have learned, and continue to learn, even more about the fascinating and mysterious world of genetics.
Deoxyribo Nucleic Aced also known as DNA is the basis of the human body. DNA is 500 times thinner than a strand of hair. It is shaped like a twisted ladder called a double helix. The rungs of the ladder are called nucleotides and are classified by letters (A, L, T, G) and each DNA strand is made of many letters. The letters form words, the words form sentences, and these sentences are our genes.
DNA is packed tightly into chromosomes. Each human cell has 46 chromosomes. Unlike humans, mosquitoes have only 6 chromosomes, while carp have 104. We receive 23 chromosomes from each parent, this is called inheritance. There are 8,388,608 possible chromosome combinations from each parent. People also inherit their parent's genes.
Genes tell the cells how to make proteins. Each cell contains thousands of proteins. Specialized proteins work in our hair cells, help us hear, and put the color in our eyes. Another example is the "receptor" proteins that send signals to tell the brain when you are in pain.
Even today we continue to make more and more discoveries about human genetics. In 1990 the U.S. began a 13-year effort called the Human Genome Project or HGP. Some goals of the HGP are to identify all of the 30,000 genes in the human DNA, improve tools for data analysis, and determine the sequences of the 3 billion chemical pairs that are in human DNA.
One recent discovery is the ability to duplicate biological material or "cloning." Cloning is when you make an exact genetic copy of something. Scientists often clone a single chromosome or DNA strand so they have more genetic material to study. In 1997, Scottish scientists were the first to successfully clone a mammal.
The advancements in the study of human DNA and the possibility of human cloning have caused some people to question the ethics of genetic study.