dna sequencing what, when, why? how? who and where? dna detective

ATGTTCTATCCCATTCATTTTGACGTTATTGTTGTTGGAGGAGGTCATGCTGGGACAGAAGCAGCTTTGGCTTCTGCTAGGATGCAATGTAATACGCTTTTGATTACTCATAATATTGATACTCTTGGACAGATGTCTTGTAATCCGGCCGTTGGTGGCATAGGGAAAGGACATTTAGTGAAAGAAATTGATGCGATGGGTGGATCGATGGCTTATGCTATCGATCAATCAGGAATTCAATTTAGAGTACTTAATAGTAGCAAAGGAGCTGCTGTTAGAGCAACACGTGCTCAGGCAGATAAAATATTATATCGTCAAGCAATACGTAGTATTCTTGAATATCAAAAATTTTTGTTGGTTATTCAAGCGTCAGTAGAAGATTTAATAGTTAGTGGGAACAAGATTGTTGGAGTAATTACTCCAAAATTAGGAATGAAATTTAGTGGTACGTCTGTTGTGTTGACAACCGGAACCTTTCTCAATGGTAAGATTCATATTGGGATGAATAATTTTAGAGGAGGTCGATCTGGAGATTCGGAGTCATCGTCATTGTTATCAGAGCGATTGAAAGAATTGTCTTTTCAGATTAGTCGGTTAAAAACGGGTACTTCTCCTCGTGTGCATACCAAAGGGATAAATTTTGGTTCTTTACGTGCACAATATAGTGATGATCCCATTCCTGTGTTTTCATTTATAGGATCTACAAAACTACATCCTACGCAGGTGCCTTGTTATATTACCCATACTAATAACAAAACACATGAAATAGTTAGATCAAATTTATATCAGAGTCCTATGTATACAGGTTTAATAAAAGGAATAGCACCTCGGTATTGTCCATCTATAGAAGACAAAATAACTCGTTTTTCAGATCGTAATGCTCATCAAATTTTTTTAGAACCTGAAGGTTTGACAACACCTGAAGTATATCTTAATGGTATTTCTACTAGCTTACCTTTTTGTGTACAAATGCAAATGATTAAATCAATTCAGGGATTAGAGAATGCTTGTATAATTAGGCCAGGTTATGCTATTGAATACGATTTTTTTGATCCTCGTGATTTAAAATTAACATTAGAGAGTAAAATTATTTCTGGATTATTTTTTTCTGGTCAAATTAATGGTACTACTGGTTATGAAGAAGCAGCTGCCCAAGGATTATTGGCCGGAATTAATGCAGCTAGGTTTTCCAAAAATAAAGAAGGATGGTACCCTAGAAGAGATCAGGCATATTTAGGGGTGCTTGTAGATGATCTCTGTACACATGGAACAGAAGAACCTTATCGTATGTTTACTTCGCGTGCTGAATATCGTCTGTCTTTACGTGAGGATAATGCTGATTTAAGATTAACTGAAATCGCGCGACAGTTAGGTTTGATAGATGAGTCACGGTGGAAAGCTTTTTGTTGCAAAAAAGAAAACATTGAAAAAGAACGTCAGAGATTACGTAATACTTATATTTTCCCGTATAGCTCAGATGTTGCACAATTAAATAATTTTCTTAAAACACCTTTAACACATGAAACAAATGGCGAAGATCTTTTGAGAAGGCCAGAAATTAATTATAAAAAGTTATCTCAACTAAGTACTTTTAGTCCATCTATATTGGATCGTCAAGTATTCGAGCAAATTGAAATTCAAATAAAATATGAAGGTTATATTCGTCATCAACAAGAAGAAATAAAGAGACATATTTATAATGAAAATACATTGTTACCGACTGATATAGATTTCAATATTGTTTCTGGATTATCTCAGGAGGTCATTGACAAACTCAATAATTATAAACCTTATTCTATTGGGCAGGCTTCTCGCATTTCTGGTATCACTCCTGCGGCTATTTCTAATTTATTGGTTTGGTTAAAAAAACAAGGTTTGTTAGAGCATAATACATGCTAATCTGTTGAATAATGTATTTTCTATTAATCAAGGTATTATTTAATTTCCTATATAGGGTGTTTGTGATTGTTACAATATGGAGAGAGTTGATCGTGTAGAAAACCGGTATATTTATGTCTTTTCCAATAATAATTTTATAGAAATAATAATAGTAATTAGATTATTATTTTAATGGGTTTGTTATGTATGGCATTATTTTTAATATTATACGGTTGTTTATACGTATCTAAATTTGCGCTTTGAATTTTTTTGAAAATAGGATTATACTGAACTTTTAGTTGTATACAAGTGTATTATTTCATATTTTTGAATAAATATACGTGCTGTACTAATGGTTATTAATTACAAGATAAATTACTTGTCGACCGAACTATAGTTCGGTCGTGTGTTTGTTTCTGTAAGTTGTAACATATTATGTGAAATTTACTAATTAATTCATAGTGTCATTTTAATTCTCTTTTATTGCATTAGTATATGGTTGTGTAAAAAGAGAGAGAGTGTTCTTGTTATTTTCTATTAGTACTAATTTTTTAAAAGTTGATGCAGGCACTGTCGTTCTTTTCGGATACAACATCATTGTAAGTTATATATAAAAATGATTTAGAATTTCGACATGTTAGTGACAAGTTGTATATCGAGGTTGTAATGTTGTATTATACAAGAACATTGTAAAATATTTATAGTATATTGCAGCCAATATTTTTTGAAAGGTGGTTTATGTCAGGAATCAAAGGCACTTCCCAAGAATATATTGGACATCATTTATATCATCTGCAATTTGATTTAAGTACTTTTTCGTTAGTGAGCTCGGAGAATACTTCTTCATTCTGGGTATTAAATGTAGATTCGATGTTTTTTTCAATATTATTGGCTACTTTATTTTTATTAATTTTCGGTCGTTTGGCTACAGTGGCAACTTATGCGGTTCCCACAAAACTGCAAGTGTTTATTGAGTTAGTAATATTGTTTATTGATAGCAATGTAAAAGATATGTTTCATGGTAAAAATAAACTAATTGCGCCATTATCTATGACGGTTTTTGTTTGGATTTTTTTAATGAATACCATGGATTTATTTCCCATAGATTTATTTCCTGCTATAGCTAAATTGTTAGGATTACCTGCTTTACGTGTTGTGCCGTCTGCCGATGTGAATATCACTTCTTCGCTAGCTTTAAATGTATTTGTACTTGTTATGTACTACAATATTTACGTTAATGGCGTTCATGGTTTTATTAAAGGACTGATGTATCATCCATTTAATCATCCAACATGTATTCCTATTAATTTTATTATTGAAGTTGTTAGTTTGTTATCTAAACCAGTATCACTTAGTCTTAGATTATTTGGCAATATGTATTCTGGTGAGTTGATTTTTATTTTGATATCTGGTTTATTACCATGGTGGGGACAATGGGTTTTAAATTTACCATGGGCTATTTTTCATATTTTAGTCGTTACATTACAGGCTTTTATTTTTATGGTTTTAACGGTGATTTATTTATCTACAGCCCATGACTCCTGTTAAAATGAATCATGTAATACAGAAGATTGCAGAGAGGTTATTATGGAACATTTAAATTTTGATATGTTATATATTGCTGCAGCAATAATGATGGGATTAGCAGCAATTGGAGCGGCTATCGGTATTGGCATCTTAGGTAGTAAATTTTTAGAGGGGGCTGCACGTCAACCAGATCTCATTCCGATCCTTCGAACTCAGTTTTTTATTGTTATGGGATTGGTTGATGCAATACCAATGATTACTGTAGGTCTTGGTTTGTATGTGATGTTTTCTGCGGTTTAACAATGAAAATTAATTGCATGTATTTATTATATTGATTATTAAATATCAGGATTTGCGCTGTGAATCTTAATGCAACAATATTAGGTCAAACTATTTCATTTGTTTTGTTTGTTTGGTTTTGTATGAAGTATGTGTGGTATCCATTTATATCTATTATTGAGAAACGCCAAAAAGAAATTTCTGATAATTTAGTTTCTGCTACTCATGCCAAAACAGAATCTGAGCGTGTCAATGCTGAAGCTTTGCTTTGTTTGAGACAGGCTCGGGTCAAAGCTCAAGAAATTATAAAACAAGCAAATAAATGTAAAATGCAAATAATTAATGAAGCTAAACATGAAGCTGAAAAGGAGCAAAGTAGAATTTTATCTCAAGCGCGAGAACAGATTATTTATGAAAGAAAACGTGTTACTGACGAATTAAGAAAGCAAATTAGCGAACTTGTAATTGAGGGTACAGAGAAAGTTATAGAACATTCTATAAATGAAATGATTGATATAGATCTTTTAAATAATATTATTAATACGTTGTCATATAAGGATTAGATGTCTAGTATGCTTGTGGTTGCGCGTACGTATGCTCAAGCTATATTTGATATAGCTGTAGAACAGAAAAATATAAACAAGTGGAAATCAGTTCTTGATTTATTTTCTGAGATTAGTCTAAATAGACTAGTACAATCTTTATTTTTTAGATGTTTAGAACCAAAAAGATTGTCAGATATATTTATTGCTATTTGTGAAGATTACCAAAAGAAACAAGTTGATACCTTCAGTAAAAATATAATCTATATTATGGCGGAAAATAATCGTTTATTATTATTACCAATTGTATTTAAAGAGTTTACTTATTTATGTTCTATATATGTTCATACTGTAGAAATAGAAATTATCTCTGCTTGGCCTTTGAAGTATAATCAGCTGAAAAAAATTACTGATATAATGGCTAAACGTTTATCTAAAACAGTGAATCCAGTACACAAAGTAGATAAAGATATATTGGCTGGTGTAATTATTCGTATTGGAGATACTGTGATTGATGGAAGTATACGTGGACGTATTTTTCGCTTAAATCACGTACTACAATCTTAATATTTTAACAGTAGTTAAAAGGTATAAACAAAAGATTATGCAATTAAATTCAAATGAAATTTCAGATAATGGAGAAGTTATTATTAATGATTTAAAGTTATTTTATAATAAAGCTAGACAAACTAAAATTACAGAAGAACTTACAGAAATTGTTTCAGGAGCTTCTGTAATATAAACTTAAAAGATAGTTAGAGGTATAATTAATATGAGTTCTGGAAAAATTGTCCAGGTTATTGGAGCGGTGGTTGATGTTGCGTTCAATCAAGATGTGGTACCGACTGTATACCATGCACTTGAGGTGTAATACTTATATTTTCCCGTATAGCTCAGATGTTGCACAATTAAATAATTTTCTTAAAACACCTTTAACACATGAAACAAATGGCGAAGATCTTTTGAGAAGGCCAGAAATTAATTATAAAAAGTTATCTCAACTAAGTACTTTTAGTCCATCTATATTGGATCGTCAAGTATTCGAGCAAATTGAAATTCAAATAAAATATGAAGGTTATATTCGTCATCAACAAGAAGAAATAAAGAGACATATTTATAATGAAAATACATTGTTACCGACTGATATAGATTTCAATATTGTTTCTGGATTATCTCAGGAGGTCATTGACAAACTCAATAATTATAAACCTTATTCTATTGGGCAGGCTTCTCGCATTTCTGGTATCACTCCTGCGGCTATTTCTAATTTATTGGTTTGGTTAAAAAAACAAGGTTTGTTAGAGCATAATACATGCTAATCTGTTGAATAATGTATTTTCTATTAATCAAGGTATTATTTAATTTCCTATATAGGGTGTTTGTGATTGTTACAATATGGAGAGAGTTGATCGTGTAGAAAACCGGTATATTTATGTCTTTTCCAATAATAATTTTATAGAAATAATAATAGTAATTAGATTATTATTTTAATGGGTTTGTTATGTATGGCATTATTTTTAATATTATACGGTTGTTTATACGTATCTAAATTTGCGCTTTGAATTTTTTTGAAAATAGGATTATACTGAACTTTTAGTTGTATACAAGTGTATTATTTCATATTTTTGAATAAATATACGTGCTGTACTAATGGTTATTAATTACAAGATAAATTACTTGTCGACCGAACTATAGTTCGGTCGTGTGTTTGTTTCTGTAAGTTGTAACATATTATGTGAAATTTACTAATTAATTCATAGTGTCATTTTAATTCTCTTTTATTGCATTAGTATATGGTTGTGTAAAAAGAGAGAGAGTGTTCTTGTTATTTTCTATTAGTACTAATTTTTTAAAAGTTGATGCAGGCACTGTCGTTCTTTTCGGATACAACATCATTGTAAGTTATATATAAAAATGATTTAGAATTTCGACATGTTAGTGACAAGTTGTATATCGAGGTTGTAATGTTGTATTATACAAGAACATTGTAAAATATTTATAGTATATTGCAGCCAATATTTTTTGAAAGGTGGGTGGATCGATGGCTTATGCTATCGATCAATCAGGAATTCAATTTAGAGTACTTAATAGTAGCAAAGGAGCTGCTGTTAGAGCAACACGTGCTCAGGCAGATAAAATATTATATCGTCAAGCAATACGTAGTATTCTTGAATATCAAAAATTTTTGTTGGTTATTCAAGCGTCAGTAGAAGATTTAATAGTTAGTGGGAACAAGATTGTTGGAGTAATTACTCCAAAATTAGGAATGAAATTTAGTGGTACGTCTGTTGTGTTGACAACCGGAACCTTTCTCAATGGTAAGATTCATATTGGGATGAATAATTTTAGAGGAGGTCGATCTGGAGATTCGGAGTCATCGTCATTGTTATCAGAGCGATTGAAAGAATTGTCTTTTCAGATTAGTCGGTTAAAAACGGGTACTTCTCCTCGTGTGCATACCAAAGGGATAAATTTTGGTTCTTTACGTGCACAATATAGTGATGATCCCATTCCTGTGTTTTCATTTATAGGATCTACAAAACTACATCCTACGCAGGTGCCT

DNA sequencingWhat, When, Why?How?Who and Where?

DNA detective

?

DNA extraction PCR

Gel electrophoresis

Insect identificatio

n

ACAGATGTCTTGTAATCCGGCCGTTGGTGGCATAGGGAAAGGACATTTAGTGAAAGAAATTGATGCGATGGGTGGATCGATGGCTTATGCTATCGATCAATCAGGAATTCAATTTAGAGTACTTAATAGTAGCAAAGGAGCTGCTGTTAGAGCAACACGTGCTCAGGCAGATAAAATATTATATCGTCAAGCAATACGTAGTATTCTTGAATATCAAAAATTTTTGTTGGTTATTCA

DNA sequencingACAGATGTCTT

GTAATCCGGCC

GTTGGTGGCAT

AGGGAAAGGAC

ATTTAG

Bioinformatics

WHAT types of biological insights can DNA sequence data can provide?

WHEN and WHY would we want to obtain this detailed information?

HOW is DNA sequencing actually performed?

WHO conducts DNA sequencing, and WHERE?

The elegant idea behind DNA sequencing

Technology changes quickly, but for many years we’ve on Sanger’s cool trick.

Fred Sanger

In the 1970’s, Sanger’s group discovered a fundamentally new method of 'reading' the linear DNA sequence using special bases called chain terminators. This method is still in use today.

What is the basis of Sanger’s method?

Shared with Walter Gilbert and Paul Berg

Fascinating. Now how do we actually sequence ??

DNA Sequencing:

Step 1: Purify template (the DNA to be sequenced)

Amplified DNA+ used Taq+ extra primer and dNTPs+ salts from PCR buffer, etc….

On to sequencing….

clean PCR product + water

PCR clean-up

Step 2: Set up cycle sequencing reaction

NUCLEOTIDES

DIDEOXYNUCLEOTIDES

TEMPLATE DNA (e.g., YOUR PCR PRODUCT)

DNA PRIMER

Today, nearly all sequencing is Fluorescence-based, and uses chain terminators that are labeled with different dyes.

The dyes are “spectrally distinct,” and each has a different emission wavelength.

denaturation

Primer annealing

Product extension

Reaction steps seems a lot like PCR, but not quite…

Step 3: Perform cycle sequencing in PCR machine

Go to:

Cycle Sequencing>> Cycle sequencing

1. Purify PCR product

2. Set up sequencing reaction

3. Perform cycle

sequencing

4. Resolve sequence fragments

5. Read order of terminators (DNA

sequence)

In sum: From PCR to sequence data

Quality of sequence data may vary, depending on:

• Purity and concentration of template DNA • Presence of extra PCR bands (artifacts)• Quality of dye-terminators, electrophoresis matrix, and other reagents

Ideally, look at chromatograms and convince yourself that base calls are robust.

DNA sequence assembly: Combining sequence reads to build the entire sequence of the template DNA

PCR PRODUCT of 1,200 bp

Sequence read #1

Sequence read #2

Sequence read #3

Sequence “reads” typically range from 500-800 bp. Often the total DNA fragment is much longer.

Regions of overlap among sequence reads:

• Let us piece together the linear “puzzle” of the template DNA sequence.

• Often confirm base calls and improve overall add data quality.