Chapter 15 Genomics
Genome: all the genes an organism has
Genomics is easier to study in bacteria
Bacterial genome
Bacteria have one chromosome (loop of DNA)
They also have plasmids, smaller loops of DNA
which may contain useful DNA
Bacteria have no introns, each gene is just one
gene with no variations
Because of introns, it is hard to identify specific
genes in eukaryote DNA
Gene libraries: collections of cells that have
particular sequences of DNA in them
Probe, complementary DNA sequence
TATGGC
ATACCG(labeled with pigment or isotope)
This allows them to identify the cell with the DNA
sequence desired
How do you make a DNA fingerprint?
Restriction enzymes cut DNA at specific sequences
of basepairs. DNA with different sequences of
base pairs get cut at different spots. Thus
restriction enzymes cut different sequences of
DNA into different size pieces.
When these fragments are pulled through a gel by
electrical attractions, small pieces et pulled farther
than big pieces. The different patterns of DNA
fragment bands are the DNA fingerprint.
To get large amounts of DNA (to work with)
PCR Polymerase Chain Reaction
Hot and cold
High temp “unzips” separates the two strands
When cooled, single stranded DNA can form new
strands by joining with free nucleotides;
Then hot again to split the new DNA strands, tehn
cool again, etc.
DNA sequencing
Two pieces of info needed (where it is in the
sequence
Labeled nucleotides (A, T, G, C each has a unique
label pigment), also modified to stop replication
(the DNA chain ends with them)
Genetic engineering
Inserting foreign DNA into a genome