You can see DNA with your own eyes tonight, using strawberries and things from under the sink. Chromosomes and living cultures take a little more equipment, and one of them takes some care.
DNA you can see, pulled out with kitchen supplies.
Pull DNA out of a strawberry
This is the version the National Human Genome Research Institute teaches, and everything in it comes from a kitchen.
You need: a resealable bag, 2 strawberries with the leaves removed, 2 teaspoons of dish detergent, 1 teaspoon of salt, 1/2 cup of water, 2 plastic cups, a coffee filter, 1/2 cup of cold rubbing alcohol and a coffee stirrer.
Mash. Seal the strawberries in the bag and squash them for about two minutes.
Mix the extraction solution. Stir the detergent and salt into the water until the salt dissolves, pour it into the bag, reseal it and massage gently for a minute. Go easy, or you get a bag of foam.
Filter. Set the coffee filter over the second cup and pour the mixture through. The pulp stays behind.
Add the alcohol. Pour an equal amount of cold rubbing alcohol into the filtered liquid and swirl the cup gently.
Collect it. A cloudy white layer forms at the top. That is the strawberry DNA, and you can lift it out with the stirrer.
See chromosomes dividing
Chromosomes are only visible while a cell is dividing, and preparing that yourself needs chemicals most homes do not keep. Prepared slides skip that step.
Onion root tip slides are the classic, because root tips grow fast and catch many cells mid-division. Look at 400X for the separate stages, with chromosomes lined up across the middle, pulling apart, then forming two new cells.
A 100-slide set that includes mitosis and meiosis slides gives you both kinds of cell division next to plant, insect and human tissue.
Grow bacteria on agar plates
Swab a doorknob, a phone or a kitchen sponge onto a nutrient agar plate and colonies appear within a few days. You cannot tell by looking which are harmless, so every plate gets treated as if it could make someone sick.
Tape the lid on right after you swab it. Two to four short pieces of clear tape hold it without hiding the colonies.
Keep plates at room temperature, upside down, for two to three days. A heat mat or the top of the fridge is a bad idea: warmth near body temperature can favor bacteria that live on people.
Never open a plate once something is growing on it. Look, count and photograph through the lid.
Wash your hands before and after, and keep food away from the plates.
When to throw a plate out early
Fuzzy mold spreading across the agar, a lid that has come loose, or a plate that cracked. Tape it shut if you can, bleach it and discard it without opening it wider than you need to.
Go further with a kit
A boxed genetics lab adds the pieces a kitchen cannot. The Thames & Kosmos lab isolates DNA from a tomato, has you build a double helix model and walks through dominant and recessive traits with inheritance games.
Genetically engineering bacteria is also possible at home. Amino Labs sells a beginner bacterial transformation kit that uses Biosafety Level 1 organisms, for ages 13 and up, direct from its own site.
CRISPR gene editing works at home too, in the same harmless E. coli. Doing CRISPR at home compares the kits and what each one edits.
Pouring your own plates starts with sterilizing the agar, and boiling isn't enough. A pressure canner does it at home, as using a pressure canner as an autoclave explains.
Kits, plates and slides on Amazon
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Prepared slides
USCAMEL 100 prepared slides
100 prepared slides covering bacteria, fungi, human tissue, plants, insects and animal cells, including mitosis and meiosis stages.
Mash two strawberries in a bag with dish detergent, salt and water, filter it, then pour an equal amount of cold alcohol on top. The white layer that forms is mostly DNA.
Wipe surfaces with a 10% bleach solution, one part household bleach to nine parts water.
