|
The Bead Game:
DNA fingerprints aren't really an event, and they're not really fingerprints either. They are, however, mighty cool. Why? Well first you need to know the deal with sequencing and minisatellites.
Here goes (100 words or less): A single strand of DNA is like a really long bead necklace made up of only four different kinds of beads. There are certain specific areas (minisatellites!) in each person's DNA necklace where these beads are always arranged differently. So you get someone's blood (or some other strategic bodily fluid) and you probe for the specific areas
|
|
(minisatellites again!) where the beads are lined up uniquely. Then you sequence those areas with some high-tech lab apparatus, and you find out exactly how the
|
 |
beads are arranged. It doesn't get more exact than that!
The common method of gene sequencing came about in 1970, and minisatellites were discovered in 1985. There are also these things called VNTRs (Variable |
|
Number Tandem Repeat), which are pretty much the same deal as minisats.
Cool thing is, the chance of two people having the same minisatellites is about one in 9 billion! So like, we can tell people apart now! Or, um, much better than we used to.
[Just to be a little scientifically responsible, we must tell you that the "beads" mentioned in the example are simply a metaphor for the bases (adenine, guanine, cytosine and thymine) which are the main components of DNA.]
|
 |
|
back to the timeline
|
|