They were talking about "DNA Dragnets" on C-Span this morning. Basically, the idea is that police request DNA samples from all possible suspects in the vicinity of a crime in which they have DNA evidence from the crime scene (e.g. asking all male nursing home workers for DNA samples after a female resident is raped and strangled, with semen left at the scene).

This sound reasonable to me, but there was the usual spate of paranoia being spouted by half the callers. They didn't want The Government having their DNA on file. Who knows what they'd use it for, right? Perhaps to make a clone of housewife Mable Johnson, have her killed by the CIA, then replace her. That's just the sort of thing our government does.

Several people were worried that the government would use information about people's propensity for diabetes or heart disease or whatever against them, by giving that information to insurance companies.

Anyway, can somebody help me out with the science here? Don't they just check a series of genetic markers to compare DNA anyway, that is, small, significant sequences that match up in both samples? Couldn't I just have a "marker profile" on file with the government, instead of my entire genome, that would reveal virtually nothing about my propensities for disease or violence or a love of chocolate sundaes?

Any geneticists in the house?