What can DNA be extracted from?

white blood cells, bones, hair follicles, preserved body parts, clothing and fiber, bodily fluids

Why can't RBC be used to extract DNA?

RBC lose their nucleus when they mature, so no DNA

Polymerase Chain Reaction (PCR)

process of copying DNA by adding a target sequence, deoxyribonucleotides, Taq polymerase enzyme, buffer, and DNA primers to a PCR tube all in a thermal cycler

thermal cycler

lowers and raises temperatures

denaturation in PCR

HEAT UP; separates complementary DNA strands

annealing in PCR

COOL DOWN, DNA primers attach to each end of the target sequence

extension in PCR

HEAT UP, Taq polymerase adds complimentary bases (deoxyribonucleotides) to build new strands

How many times can PCR repeat?

30-40 times in an hour

restriction enzymes/endonucleases

cut DNA in specific places called recognition sites in the process of restriction dig

How are recognition sites symbolized?

^

Where are restriction enzymes sourced from?

bacteria who use it to defend against viral DNA

How are restriction enzymes named?

bacterial source, strain / genetic variant, and order of discovery (e.g. Escherichia coli from the RY13 Strain discovered first --> EcoRI)

blunt ends

created by restriction enzymes that cut straight down the middle

sticky ends

created by restriction enzymes that cut jaggedly (diagonally)

gel electrophoresis

the process of separating and comparing DNA pieces, uses agarose gel and buffer

agarose gel

made from agar (from seaweed), porous

What pieces of DNA in gel electrophoresis travel farthest?

smaller pieces can move through the pores more easily, so travel farther

What distance do DNA pieces that are the same size travel?

at the same rate, landing in the same place

buffer

a chemical solution that conducts the electric current in gel electrophoresis

loading a gel

the process of adding DNA before running gel electrophoresis

well

indentations in the gel, made using a comb while the gel is setting

lane

the area the DNA travels down

loading dye

mixture of dye (e.g. blue) and sugar (e.g. glycerol)

What is dye used for in gel electrophoresis?

to visually track DNA's migration through the gel (run ahead since they are smaller than DNA)

What is the sugar used for in gel electrophoresis?

heavier than DNA, so binds to it and sinks it to the bottom of wells (prevents from floating away in the buffer)

What side of the electrophoresis chamber is the DNA placed in?

the negative side; DNA is negatively charged so will move to the positive side

DNA ladder/marker

the standard for comparison for DNA base pair (bp) measures, made of known DNA fragment sizes

restriction fragment length polymorphism (RFLP)

the different patterns of DNA fragments resulting in variation in DNA sequences recognized by restriction enzymes, "unique DNA fingerprint"

micropipettes

transfer microvolumes of liquid

CODIS

U.S. national DNA database with DNA of convicted criminals, unidentified human remains, missing persons and their relatives, and crime scene DNA samples