Passing Genetic Notes in Class

Passing Genetic Notes in Class

CC106 / Discussion D

by John R. Finnerty

BioUNITYBioUNITY

Bacteria EukaryotaArchaea

LUCALast Universal Common Ancestor

metabolism protein assembly genetic material genetic code

Unity & Diversity

Metabolic Unity

Use the same enzymes to digest sugars.

Molecular Unity

Use the same molecular machinery to build proteins.

Genetic Unity

Use DNA & RNA to transmit encoded information.

& use the same genetic code.

LEUCINEISO-

LEUCINECYSTEINE

DNA alphabet

Portion of a gene

RNA alphabet

Protein sequence

c

-C-T-A-T-T-A-A-G-T-

-C-U-A-U-U-A-A-G-U-

gene is transcribed into a “message”

message is translated into a protein using the genetic code

-G-A-T-A-A-T-T-C-A-

string of amino acids L I C

Human insulin gene

E. coli bacterium

Human insulin protein

Implication of Shared Genetic Code

Key Properties of the Code

Each codon (= word) is 3-letters long. There is a reading frame.The code is redundant: multiple words say the same thing.The code is somewhat robust to errors. Not all mutations (= spelling mistakes) change the meaning.

I. Using the 1-letter abbreviations for amino acids, compose a note instructing your teammates to perform some action.

20 available letters: A C D E F G H I K L M N P Q R S T V W Y

II. Reverse translate your protein note into DNA letters (ACGT) using the genetic code.

C T A G A A G C C A A T

II. Reverse translate your protein note into DNA letters (ACGT) using the genetic code.

C T A G A A G C C A A T

IIa. Add 0, 1, or 2 dummy letters at the beginning and end to hide the reading frame.

C G A

III. Transmit note, now encoded in DNA form to another team, who will mutate 1 of every 5 letters.

IIIa. Pass mutated message to intended recipients.

C G C T A G A A G C C A A T AC G T T A G A G G C C A A A A

C G T T A G A G G C C A A A A

IV. Recipients translate message (after being told the correct reading frame).


R STOP R P K

IV. Recipients translate message (after being told the correct reading frame).


R STOP R P K


L E A K

V. Deduce what the message is supposed to say.


L E A K

Clues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).



L E A KC G T T A G A G G C C A A A A

P E E KClues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).



L E A KC G C C A G A G G A AA A A A

P E E KClues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).



L E A KC G T T A G A G G C C A A A A

L E A PClues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).



L E A KC G T T A G A G G C C C C A A

L E A PClues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).



L E A KC G T T A G A G G C C A A T A

L E A NClues: should direct me to perform an action.Message would be mutated in 3 places.But, not all DNA mutations would change the meaning of the message (the amino acid).

T C A G

TTTTTTCTTATTG

FFLL

TCTTCCTCATCG

SSSS

TATTACTAATAG

YY**

TGTTGCTGATGG

CC*W

TCAG

CCTTCTCCTACTG

LLLL

CCTCCCCCACCG

PPPP

CATCACCAACAG

HHQQ

CGTCGCCGACGG

RRRR

TCAG

AATTATCATAATG

IIIM

ACTACCACAACG

TTTT

AATAACAAAAAG

NNKK

AGTAGCAGAAGG

SSRR

TCAG

GGTTGTCGTAGTG

VVVV

GCTGCCGCAGCG

AAAA

GATGACGAAGAG

DDEE

GGTGGCGGAGGG

GGGG

TCAG

Th

ird

let

ter

in c

od

on

Second letter in codon

Fir

st l

ette

r in

co

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Passing Genetic Notes in Class

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