Questions for chapter “Timeline of genome sequencing”
1. Study the timeline on the first page of the chapter. Make your personal top 5 of the key
moments in the history of genome sequencing. For each of the 5 items, explain why
you think it belongs to the top 5.
1.complete human genome
2.Watson & Crcik double helix modal
3.Sanger sew.
4.Isolation DNA
5.Taq polymerase
2. In 1973, a method was invented to clone DNA fragments in bacteria. Why was this
invention important?
To make more DNA fragments -->amplified it, otherwise signal is way to weak.
3. In 1977, Frederic Sanger developed a method to sequence DNA.
a. What was the goal of this method?
Base-by-base sequencing
b. Why was it necessary to add 1 modified nucleotide to each sample mixture?
Describe the difference between a normal and modified nucleotide in your own
words, and explain why this difference is important.
Modified nucleotide is the dideoxy nucleotide. They have no O group to 3’. So,
terminate the chain.
Do this with different nucleotides and sequence can be read by gel electrophorese
The band will correspond to the chain length.
c. If you want to sequence a DNA genome of 100 base pairs using this method,
how would you do that? How many Eppendorf vials would you need to make?
How would the gel for separation look like? And how would you read the
sequence from the gel?
Eppendorf vials; 4 vials, for each base pair (GATC)
Gel look like; 4 lanes with bands (lane for G, A, T and C)
How read sequence; bottom to the top
4. Later, the sequencing method was improved and accelerated. Draw how a PCR
reaction with 2 primers can yield an exponential amplification, whereas a cycle
sequencing reaction with 1 primer will yield a linear amplification. Tip: draw both parent
DNA strands, the primers and the products of the two first cycles.
Cycle sequencing and PCR zie schrift
5. Describe how the use of dyedeoxy nucleotides made the Sanger method 4-fold more
effective.
By four color/one lane sequencing technique; the dideoxy nucleotides are labeled with
fluorescent dye. Instead of having to perform 4 sequence reactions, all four nucleotides
could now be read from a single sequence reaction, so 4-fold more effective.
1. Study the timeline on the first page of the chapter. Make your personal top 5 of the key
moments in the history of genome sequencing. For each of the 5 items, explain why
you think it belongs to the top 5.
1.complete human genome
2.Watson & Crcik double helix modal
3.Sanger sew.
4.Isolation DNA
5.Taq polymerase
2. In 1973, a method was invented to clone DNA fragments in bacteria. Why was this
invention important?
To make more DNA fragments -->amplified it, otherwise signal is way to weak.
3. In 1977, Frederic Sanger developed a method to sequence DNA.
a. What was the goal of this method?
Base-by-base sequencing
b. Why was it necessary to add 1 modified nucleotide to each sample mixture?
Describe the difference between a normal and modified nucleotide in your own
words, and explain why this difference is important.
Modified nucleotide is the dideoxy nucleotide. They have no O group to 3’. So,
terminate the chain.
Do this with different nucleotides and sequence can be read by gel electrophorese
The band will correspond to the chain length.
c. If you want to sequence a DNA genome of 100 base pairs using this method,
how would you do that? How many Eppendorf vials would you need to make?
How would the gel for separation look like? And how would you read the
sequence from the gel?
Eppendorf vials; 4 vials, for each base pair (GATC)
Gel look like; 4 lanes with bands (lane for G, A, T and C)
How read sequence; bottom to the top
4. Later, the sequencing method was improved and accelerated. Draw how a PCR
reaction with 2 primers can yield an exponential amplification, whereas a cycle
sequencing reaction with 1 primer will yield a linear amplification. Tip: draw both parent
DNA strands, the primers and the products of the two first cycles.
Cycle sequencing and PCR zie schrift
5. Describe how the use of dyedeoxy nucleotides made the Sanger method 4-fold more
effective.
By four color/one lane sequencing technique; the dideoxy nucleotides are labeled with
fluorescent dye. Instead of having to perform 4 sequence reactions, all four nucleotides
could now be read from a single sequence reaction, so 4-fold more effective.
