Can DNA remains be left if someone shakes hands with someone else?

Question

I was convinced that DNA could only be checked from samples of (significant) body tissues (or fluids), such as saliva, sweat, blood, sperm...

(And even these samples could only provide results if analyzed within a certain ammount of time...)

I can't believe that people are able to make serious accusations based on some 'alleged biological remains', which seem comparable to 'dust' or so...

Answer 1

DNA is present in (almost) all of the cells of your body. It is therefore present in blood (in white blood cells), saliva (in sloughed-off oral epithelial cells), sperm (in large quantities, in all the sperm cells).
It can also be found from hair samples (as long as the hair follicle, containing cells, is still attached).

Your body sheds around 1300 dead keratinocytes (skin cells) per cm2 of skin per hour, so shaking hands with someone *will* leave lots of cells behind. However, mature keratinocytes (like red blood cells) are one of the cell types that do *not* contain a nucleus.

On the other hand, if you were to scrape yourself against something, this might penetrate to a deeper layer of skin. You only need to go in two layers - to the Stratum Granulosum - to find living cells, with nuclei. And this is only about 1mm down at the most (though it varies by location on your body).

So - skin flakes have no DNA, and cannot be used, but scrapings do, and can.

Answer 2

The DNA molecule is incredibly tiny. It fits inside a single cell, remember. So theoretically, even something as small as a grain of dust is enough to contain DNA.

But as a practical matter, it may take more than that to reproduce enough DNA to run a good test. And another problem is contamination. How do you know that bit of DNA came from a particular person. If you shook hands with 2-3 people, or touched a light switch, or picked up an object that someone else handled, you could have DNA from them as well. The best results come from using controlled collection techniques, where the mouth swab, blood sample, etc, is collected and stored and labelled using proper technique.

Answer 3

it depends. this is possible if loose cells got the chance to adhere to the other person's hands during the action (since DNA could be isolated from the nucleus within a cell). of course the cells may not strictly come from the palm. the hands might have rubbed with other parts of the body (or come in contact with body fluids) and incidentally caught some loose cells. the chance of "transfer" however may be slim. hands that are sweaty might increase the probability. do you always have "clean hands" when you doing a handshake? :-)

Answer 4

relies upon on who extends their hand first and if that individual is left-exceeded or appropriate-exceeded some women shake hands, some do no longer some adult adult males shake hands, some do no longer some authority figures shake hands, some do no longer the hand shaking element seems to be susbsiding as a results of fact of cultural/generational alterations and hygiene

Answer 5

It is true - it is known as 'transfer' if your DNA is found on someone else, it doesn't even have to be a fingerprint. Similarly, you can transfer DNA of someone you have touched onto someone else.