DNA is the genetic material

Transforming Principle

Phage T2

Transfection

•DNA is the genetic material in eukaryotes

•It can be transferred between different species and yet remain functional

DNA is a double helix

Nucleic acid

Nucleosides

Sequences of bases is the form in which genetic information is carried

Watson & Crick DNA double helix•X-ray diffraction data

•Constant diameter of DNA

•G= C, A=T

Mutations change the sequence of DNA

Mutations

•Spontaneous - Due to normal cellular operations

•Induced mutations - Due to mutagens

Nitrous acideffect

BrdUeffect

Triplet code

Triplet code

•Genetic code

•Genetic information

•Codon

Frame-shift mutations

Genetic code

•No overlapping

•Use fixed starting point

Blocked reading frames

mRNA

Gene may be longer than Prt sequence

Gene may be longer than Prt sequence

Eukaryotic genes are often interrupted

Organization of interrupted genes may be conserved

Globin genes

Introns in Vertebrates

Exons in Eukaryotes

C-value

C-value

C-value

Amino acidsProteins are dehydration polymers of amino acids

All 20 common amino acids are α-amino acids

They differ from each other in their side chains, or R groups

Stereoisomerism

Classification

Classification

Classification

Classification

Classification

Twenty publications that influenced present view