DNA, a primer
So, I'm not a rocket scientist. In fact, the more I learn the more I realize how little I really know. One of my favorite things to teach in biology is DNA and genetics. Since I'm home with Re-Pete today, thought I might bring some schooling to all y'all.
All living things have genetic material. Some organisms, like bacteria, have little rings called plasmids. Scientists take advantage of these by inserting little bits of our DNA into the rings. Then the bacteria make whatever we've programmed them to, say, insulin. There are huge sterile vats of a sugary solution containing billions and billions of bacteria eating all that glucose goodness and happily shitting out human insulin. It's a win-win situation. There's a company making Lysix, bacteria with a purpose! I think this is going to revolutionize the lunchmeat industry. No more Listeria, the culprit in many food poisonings. This bad boy can kill an unborn child, which is why pregnant women are cautioned not to eat cold cuts.
Even viruses, not technically a living thing, contain genetic material. Viruses work by shooting their genetic wad into specific cells. Now, if you're a smoker, you probably have the tobacco mosaic virus inside you. Why haven't you broken out? Because you don't have living tobacco cells inside you. Warts are caused by viruses putting their DNA into your skin cells.
Here's the thing: all DNA is made of the same basic stuff- sugar, phosphates, and 4 bases, A,T,C, and G. All living things have those same 6 ingredients, nothing more, nothing less. How cool is that? You share the same type of genetic material as the cow you had for dinner, or the snake you shot, or the plant material you smoked.
So, the questions begs to be asked- If we all have the same DNA, how come we don't have camel-dogs and sheep-boys? It's all about the arrangement. DNA is arranged into chromosomes. For a new living thing to begin those chromosomes from the male and the female species must match up in number and size. When they almost match up, but not quite, defects occur. If there is a great discrepancy, fertilization won't occur. But that's another story.
There will be a quiz on this tomorrow. Time for recess.
update: Ellison got me thinking:
humans- 46 chromosomes (normally)
corn- 20
humans- 25, 000 genes
corn- 59,000
humans- 3,300 million base pairs
corn- 2,500
see here for more info
5 comments:
I think genetics is fascinating. I've learned a lot in the last eight years. The fact that I understand that a single protein, arginine, stopped growing at 1069 instead of 3000 on exon 11 of the CHD7 gene on the eighth chromosome is why my daughter has CHARGE syndrome amazes me. I had a great teacher from Baylor College of Medicine in Texas who explained it all to me. If I was more mathematically/scientifically inclined, I would love to be involved with genetics somehow.
I think I saw sheepboy on the drive to Helen. He was standing next to an EXTREME METH MAKEOVER! billboard.
Makes you wonder how Superman could ever father a child on Lois Lane - assuming he didn't blow her apart when he shot his wad, that is. I mean, Superman being an alien and all, his DNA probably has less in common with ours than ours has with an ear of corn.
Only you would think of that Elisson...ha ha ha
Can you explain Velociman's mutant, genetically? I don't know how he got it, but it probably wasn't pretty.
'Neck
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