How can a dna molecule help figure out if someone is the parent of a child?

Question

How can a dna molecule help figure out if someone is the parents of a child?
like what are scientists specifically looking for.....
like the traits or what

Answer 1

DNA fingerprinting relies on a specific region of DNA that doesn't do anything. Actually, about 90% of your DNA doesn't do much of anything, but the section that's used for DNA fingerprinting has done nothing for so long that random mutations have made the section... well... random. A typical 'fingerprint' includes 13 units, each of which has from 5 to 20 variations in the population.

So basically scientists can analyze this one area of DNA and come up with a pattern that is ALMOST unique to you. Given the above variation in the units they use, the chance that a total stranger happens to have the exact same sequence can be as small as one in a quintillion. Since there's less then 10 billion people on earth, it is so fantastically unlikely that any two people have the same strands by chance that most would agree that it probably just isn't going to happen.

And that's where the 'almost' comes in. Any child will have two copies of this random sequence, one from each parent... and since copy errors are fairly common, it's possible even that it's very slightly different from each. Still, a slight difference is quite different from total randomness. Thus DNA fingerprinting can usually determine if someone is a parent or not with better than 99% accuracy, and tell if any trace DNA is yours with perhaps more accuracy than that, depending on how much time the particular piece of DNA has had to degrade and the like.

Answer 2

Through electrophoresis. Take a piece from the baby, dad#1, and dad#2. Radioactively tag a gene that would be in the same place on dad/baby but would be in different places on a strangers gene. Run them thru the gel. As the pieces are pulled through the gel, the similar strands go similar distances thru the gel. They cause bands along their journey b/c radioactive tags on the genes. When the bands match up in distances for two individuals those two people are related. You can also test a suspect DNA to a murder scene DNA, b/c if the DNA goes the same distance through, then they are a match.

Answer 3

Well, DNA between human beings is full of what we call polymorphic sequences. That is, even though our genomes are > 99% the same, there is still a little bit of variation from person to person in the nucleotide sequence. A technology called DNA fingerprinting can be used to differentiate one human being's DNA from that of another human being. Just think of it as being analogous to an actual fingerprint--just like nobody else in the world has the same fingerprints as you, nobody else in the world shares the exact same genome sequence.

More on fingerprinting here: http://en.wikipedia.org/wiki/Genetic_fingerprinting

Hope that helps.

Answer 4

A child has copies of his parental genes.