I was thinking about this. This method of testing would never work at my house because we have frequent deliveries, guests and workmen and I'm certain our trash contains all of their different DNA's on water bottles and other disposable items, like Kleenex, paper towels, napkins, disposable cups, disposable guest towels, liquid soap containers and whatever they brought with them such as boxes, plastic wrap, etc and I'm sure the deliveries contain DNA from whoever packed them and groceries probably have DNA from where they were manufactured, the people who packed them for shipment, the people who transported and moved them, the people who unpacked and stocked shelves, then anyone who might have touched the item before me, me the purchaser, the checker and bagger and finally the person who put them in my vehicle. The odds of being able to select one person's DNA out of our trash would be tiny. In just a week there might well be thousands of different people's DNA on our trash. That must have been a daunting prospect to weed out a piece of trash from one person.
I think it would work, since I've collected trash and teach a lab that includes collecting, preserving and describing trash (preliminary to forensic work).
LE and forensic workers are trained.
You go for things that look like they came from the bathroom trash. It's rare for workmen and housekeepers and DoorDash drivers to use the bathroom, but no worries -you're not looking for THEIR DNA, you're looking for Kohberger DNA.
So, in additional to bathroom trash (kleenex, discarded toothpaste tubes, paper towels, perhaps paper cups - frequently used in bathrooms) we look for:
Other paper towels
Paper and plastic cups
Tissues that could be used to clean eyeglasses (they knew Mr Kohberger wore glasses)
Food packaging (it's really rare that DoorDash or delivery people open up the lunch meat and make a sandwich)
The trash bags themselves (ditto - most of the time, DoorDash people or delivery people do not take my trash out for me)
But none of that matters because you're not looking for OTHER DNA. You start testing the most likely object and it only takes one (although, frankly, I'd be interested in more testing, as I'm that's how I roll and that's how the geneticists I admire roll).
Just think what a win it would be if Mr. Kohberger shaves! (He sure looks like he shaves). The discarded razor blades are DNA gold. He might not discard them daily, but he does discard them sometimes. Or nicks himself and dabs with a tissue. Or throws away a tube of toothpaste (and it didn't really matter which parent was tested - but I understand why they used the paternal DNA in the PCA - I'm sure they have both parents' DNA at this point).
Mr. Kohberger might not do much in the way of brushing his hair, although he definitely has hair and might actually brush it. Most people who brush their hair toss the hair from the brush (I do it daily, as do many people I know - but at least once a week, right?)
As for other parts of the trash, lots of people use paper plates and cups when they eat. Not too many use plastic silverware, but while eating, the utensils touch the plates. Cups are better. Soda cans are great. Unless the Kohbergers are unusual, they occasionally have soda or drink from a water bottle or throw away food that they prepared using their hands (potato peels, egg shells, etc). All will have your DNA on them! And they will know they've found what they're looking for when it's a 49% or higher match with the suspect DNA.
Christmas wrapping paper. Christmas boxes. Plastic bags unpacked by someone putting away groceries. SO many sources. And again, never had anyone else put away my groceries (usually just me - but sometimes husband). His DNA would be all over the big jugs of water we sometimes buy. And, of course, he too brushes his hair. Some people run their shaving byproducts down the drain, but many do not (wipe them up and put them in the trash - otherwise, things clog!)
I'm sure others can think of many other vectors. We throw stuff away daily, touched mainly by ourselves. Doesn't matter who else's DNA is on there - LE is not looking for a new suspect.
They're looking for a match to a person with a white Elantra and a particular set of DNA nucleotides. I bet they found several objects and were able to find a complete profile (which would be typical if a person ever uses a tissue or a paper cup or a soda can). Many people have favorite beverages that they sip directly from the container. SO many options.
Old paperwork is great, too. And packaging is so useful (every time we open a new package of anything - we leave our DNA on the packaging, which we throw in the trash.
Keep one's DNA out of the trash would require effort (and some secrecy or oddball practices, IMO).
Don't be so sure it woudn't work at your house - the delivery person's DNA doesn't replace yours - just is in addition to yours. No one was looking for random delivery guy. If one of your genetic relatives committed a serious crime and you went on with your regular trash disposal mechanisms (not realizing that person was a suspect), I'm pretty sure we could find your DNA on some object in the trash (along with other people's of course - although in different proportions). Cast off chapstick is great. Old socks and cast off clothing is also good. But Christmas brings a plethora of choices - as most family members touch many things inside their house, only to discard packaging, gift wrap, etc.
I forgot junk mail! Very few delivery people touch my junk mail - just the postman. But if they were looking for one of my kids - the postman is irrelevant (although possibly now in some database as John Doe).
www.documentcloud.org
