Facts About DNA and Genes
DNA Strength, Viral DNA, Jumping Genes and Mitochondrial Research
Jan 8, 2009
It’s normal to perceive DNA as small – after all, in humans, most of the cells it resides within cannot be seen without a microscope. However, it is a large molecule, but difficult to see because it’s supercoiled in chromosomes. If it were to be uncoiled, the DNA in one somatic cell would be over six feet long.
DNA is a Durable Molecule
DNA is strong as well as long. In the right conditions, it can stay together for thousands and thousands of years. Frozen mammoths are a good example. In November 2008, Nature published "Sequencing the nuclear genome of the extinct woolly mammoth". Authors Miller, W (et al) showed that about 80% of the woolly mammoth genome has been identified.
Viruses Contain DNA But May Not Be Alive
Viruses are essentially pieces of DNA (or RNA) encased in protein, copying to healthy cells and overwriting the DNA with their own. However, whether they can be considered alive is debatable. Without healthy cells to infect, viruses don’t do anything.
Since a virus copies new DNA into cells, they are of great interest to those researching gene therapy. Harnessing this and controlling the viral genetic material could allow scientists to develop treatments for illnesses such as cancer.
Genes Can “Jump” Between Chromosomes
Scientist Barbara McClintock studied chromosomes in the 1940s and 50s, and suggested that genes are able to move, not only on the chromosome, but from one chromosome to another. This idea was rejected at the time, however, McClintock was correct. She was awarded the Nobel Prize in 1983, when she was 81 years old.
Most Europeans Are Related to One of Seven Women
In his book The Seven Daughters of Eve, published by Corgi in 2001, author Brian Sykes speaks of how the current Europeans on Earth are descended from seven prehistoric women. This is based on research into mitochondrial DNA, non-nuclear DNA that is passed from mother to offspring.
Maternal lineages for other continents have also been researched. According to the Maternal Ancestry pages on the Oxford Ancestors site, there are currently thirty-six daughters of Eve known. In this context, the name “Eve” refers to “Mitochondrial Eve”, the common female ancestor of all people alive today.
For more information on basic genetics, including genes, DNA and chromosomes, read Basic Cell Biology for Understanding Genetics and Introduction to the Terminology used in Genetics.
Sources
Taking DNA Samples, Explore Forensics website, accessed: 7th January 2009, no author specified.
Barbara McClintock (Women Pioneers in Plant Biology), American Society of Plant Biology website, accessed: 7th January 2009, no author specified.
The Genetics of Viruses and Bacteria, La Cañada Unified School District website, accessed: 7th January 2009, no author specified.
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