Modern DNA Sequencing, MOJE STUDIA Toksykologia i Mikrobiologia środowiska (Ochrona Środowiska - dzienne), ...
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MODERN DNA
SEQUENCING
What & Why?
•
“
Sequencing
”
means finding the order
of nucleotides on a piece of DNA .
• Nucleotide order determines Amino acid
order, and by extension, protein
order, and by extension, protein
structure and function (proteomics)
• An alteration in a DNA sequence can
lead to an altered or non functional
protein, and hence to a harmful effect
in a plant or animal
What & Why, Ctd.
• Understanding a particular DNA sequence
can shed light on a genetic condition and
offer hope for the eventual development of
treatment
treatment
• DNA technology is also extended to
environmental, agricultural and forensic
applications
DNA Sequence variation can change the Protein
produced by a particular gene
Gene A
from
per son 1
Codon resul t s in
part icu lar Am ino
Acid ( AA) sequ enc e
GCA
AGA
GAT
AAT
TGT
Ala
Arg
Asp
Asn
Cys
Gene A
from
per son 2
Codon chan ge
m akes n o differen ce
in AA
( redu n dant code)
GC
G
AGA
GAT
AAT
TGT
Ala
Arg
Asp
Asn
Cys
Gene A
from
per son 3
Codon chan ge
resul t s in diff erent
AA sequ ence
GCA
A
A
A
GAT
AAT
TGT
Ala
Lys
Asp
Asn
Cys
Simple point mutations such as this can cause
altered protein shape and function.
Diseases such as Sickle Cell Anaemia and Cystic
Fibrosis are caused by point mutations
Historically there are two main methods
of DNA sequencing:
Maxam & Gilbert
, using chemical
sequencing
sequencing
Sanger
, using
dideoxynucleotides
.
Modern sequencing equipment uses the
principles of the Sanger technique.
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