1905-1940 Levene 利文 D-ribose in RNA and deoxyriobse in DNA Phosphate-sugar-base Nucleotide 核苷酸 Tetranucleotide hypothesis 四核苷酸假說：(dGMP-P-dCMP-P-dTMP-P-dAMP-P-)
1928 Griffith 格里菲斯 研究肺炎鏈球菌-莢膜與致病能力 Found “transformation 基因轉移 ” between bacterial cells. 1944 Avery 埃弗里 The transforming material was DNA 使用酵素分離技術，分離純化蛋白質、核酸、DNA，確定遺傳物質
The “father of genetics” 遺傳學之父
Advanced the principles of segregation 分離律and independent assortment 自由分配律
Found nuclein 核素/細胞核 in pus cells 膿細胞
(published in 1871)
Analysis the components of nuclein
Discovered adenine, guanine, thymine, uracil and cytosine 發現含氮鹼基
sex-linked genetics 性聯遺傳and
genetic recombination 基因重組（非自由分配）
D-ribose in RNA and deoxyriobse in DNA
Phosphate-sugar-base
Tetranucleotide hypothesis 四核苷酸假說：(dGMP-P-dCMP-P-dTMP-P-dAMP-P-)
研究肺炎鏈球菌-莢膜與致病能力
Found “transformation 基因轉移 ” between bacterial cells.
The transforming material was DNA
使用酵素分離技術，分離純化蛋白質、核酸、DNA，確定遺傳物質
pyrimidine = purine
A=T; C=G
推翻四核苷酸假說