Total purines=Total pyrimidines i.e., A+G=T+C.Note their very conservative, understated conclusion: вЂњThe evidence presented supports the belief that a nucleic acid of the desoxyribose type is the fundamental unit of the transforming principle of Pneumococcus Type III.вЂќД¬hargoff (1952) showed that DNA existed with enough structuralcomplexity and diversity to allow it to be THE genetic material of allorganisms.Read the accompanying text to see what was involved in this proofвЂ¦note that much of the proof was indirect and involved eliminating other possibilities!.Note also that the experiment in figure 6-3 showed that a вЂcell-freeвЂ™ substance was the вЂњtransforming principleвЂќ.ДЄvery, MacLoed and McCarty experiment, fifteen years later,proved that DNA was the вЂњtransforming principleвЂќ.This was called transformation and it was said that a вЂњtransforming principleвЂќ was involved.Note that something from the dead smooth strain (S-III) was capable of changing (transforming) the non-encapsulated, rough (R-II) mutant into a S-III strain!.How does the bacterial capsulerelate to the disease process? pneumoniae and whatdisease does it cause in mice and man? The Griffith Experiment with Streptococcus pneumoniae(1928) Figure 6-2: Patterns of genetic traits inheritance was described and began to be associated with specific chromosomes.Patterns of mitosis and meiosis was known.Nucleus contained вЂњchromosomesвЂќ and chromosome number was unique to a species.Egg and sperm nuclei fuse to form a zygote that can develop into a functional organism.Knew that the nucleus had a unique chemical composition, first call вЂњnucleinвЂќ now called DNA.Early observations (see the list on page 99-100):.How do we know that DNA is the genetic material of mostorganisms? It must be transmitted from parent to progeny without change.It must be capable of accurate replication.It must be capable of being expressed when needed.The Basic Requirements for Genetic Material (i.e., thematerial that determines the inherited characteristics of a functionalorganism):

Store and transmit genetic information