Friday, December 5, 2008

Quick Genetics Lesson- Why Jurassic Park is still Science Fiction

DNA-Deoxyribonucleic Acid-the universal genetic code. This amazing molecule codes for everything about us. For about 150 years, Biologists have wondered where we get our characteristics. Readers, I've decided to do a quick basic lesson on Genetics to clear up any confusion you may have with Crichton in Jurassic Park and all this talk of heredity and DNA sequences and jargon that make you go "Huh?"

Here's a basic Timeline on DNA studies:

  • Mid 1800s: Johann Gregor Mendel (1822-1884), "Father of Genetics", discovers the fundamental laws of inheritance through his eight year work on interbreeding pea-plants. This idea deals with dominant and recessive traits that are inherited from parents to offspring. He published his findings in 1865.

  • Mid 1800s: Fredrich Meischer (1844-1895), discovered the FIRST crude fragment of DNA that he named Nuclein. He found bandages from a nearby clinic and washed the pus off the bandages and isolated the molecule around 1876 or so.

  • Late 1800s: Thomas Hunt Morgan (1866-1945), discovered the chromosomal theory of inheritance with fruit flies. He won the Nobel Prize in 1933.

  • 1920s-1940s: Geroge Beadle discovered that bacteria can mutate by absorbing DNA from their environment.

  • 1950s: Rosalind Franklin stretched a molecule of DNA in a long tube and fired X-rays at it. The rays diffracted and formed an x-shaped photograph on paper. The shape gave clues as to the shape of DNA. The shape implies a Double Helix. This was expanded by Francis Crick and James Watson in the early 1950s. Crick (now dead) expanded his thoughts on the subject with the Central Dogma. (too complicated to explain.)

  • --50 years later-----

  • 2003: The Human Genome Project was completed. Human DNA has been completely sequenced.

DNA basics:

DNA is made of the sugar Deoxyribose, and is an acid. The "rungs" of the molecule are made of a phosphate group linked to a deoxyribose sugar which are linked to one of four nitrogenous bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). A fits with T and C fits with G and vice versa. The bases are linked by weak Hydrogen bonds so it can easily replicate. When it replicates, the molecule unwinds, and an enzyme called DNA Polymerase moves down the bonds and "unzips" it. Then another strand comes and fits with correct corresponding base. This happens in the Cell's nulceus. The molecule replicates when the cell divides. That's DNA basics for you. Also, to extract DNA, the lower the temp., the better perserved DNA stays when the cell gets dissolved.

However, as the animal dies, and the cells and tissues deteriorate, so does the DNA. Thus, by the time an animal is fossilized, you have fragmented and dead Deoxyribonucleic Acid. The same holds true for the amber in a mosquito idea. The Mosquito's dead therefore it's genetic material is too.

Maybe? Maybe Not? Certainly NOt in 2008!


Naveed said...

Quick and confusing...excellent...I'll never understand genetics. lol

Raptor Lewis said...

It's not that hard. It just requires more thought than other things. Something you're more than capapble of achieving, Naveed. Besides, I didn't provide a good explanation. Re-read it and get back to me.