1. INTRODUCTION TO GENETICS

2. Genetics is the study of heredity, the process in which a parent passes certain gene onto their children. A person's appearance – height, hair color, skin color, and eye color -- are determined by genes. Gene: a gene is a nucleotide sequence in DNA that specifies a polynucleotide or RNA.

4. 1950 – First X-ray pictures of DNA (Franklin)

5. 1953 – DNA structure revealed (Watson and Crick)

6. 1970 onwards - Multiple conformations and structures, initially from fibers

7. 1973 - X-ray structure confirms double helix (Rich)

8. 1974 - t-RNA structure (Kim)

10. In Prokaryotes:- DNA is not separated from the rest of cellular components. In eukaryotes :- DNA is located in the nucleus , and separated from the rest of the cell by nuclear envelope.

11. DNA is bound to proteins forming a complex called chromatin. Less than 0.1% of the total DNA in a cell is present in mitochondria. Euchromatin= diffuse chromatin Heterochromatin= dense chromatin

12. Chromosome In eukaryotic cells, a linear structure composed of a single DNA molecule complexes with protein. 23 pairs of chromosomes P= petit (small)

13. Chromosome Number in Various Organisms Organism Total Chromosome Number Human Chimpanzee Dog Cat Mouse Mosquito Potato Tomato 46 48 78 72 40 6 48 24

14. Histones Electron micrograph of nucleosomes Attached by strands of nucleic acid.

15. Solenoid

16. H3-H4 tetramer H2A dimer H2B dimer

17. DNA Strands

18. Watson and Crick’s double-helical model of DNA The DNA molecule consists of two polynucleotide chains wound around each other in a right-handed double helix

19. 2. The two chains are antiparallel. 3. The sugar-phosphare backbones are on the outsides of the double helix, with base orientated toward the central axis. 4. The bases in each of the two polynucleotide chains are bonded together by hydrogen bonds. The specific pairings observed are A bonded with T (2 hydrogen bonds) and G bonded with C ( 3 hydrogen bonds) and its according to Chargaff’s rule. They are called complementary base pairs. 5.The base pairs are 0.34 nm apart in the DNA helix. A complete turn (360˚) turn of the helix takes 3.4 nm, therefore there are 10 base pairs per turn. 6.

22. Guanine (G)

23. Cytosine (C)

24. Thymine (T)O O H OH C C O C C 1 1 4 4 Uracil (U) instead of Thymine in RNA. H H H H H H SUGAR 2 2 3 3 C C C C O H OH H OH Deoxyribose (DNA) Ribose (RNA)

25. CHO CHO CHO OH C H OH H C H C H Reduction OH H C OH OH H H C C OH H C OH OH H H C C CH2OH CH2OH CH2OH D-Ribose 2-deoxy-D-Ribose D-Ribose

26. Alpha and Beta Anomers CHO OH H C OH C H OH C H OH C H OH C H Hemiacetal linkage formation Hemiacetal linkage formation C H OH C OH H C OH H OH H C O O OH H C OH H C OH H C H C H C CH2OH CH2OH CH2OH D-Glucose Beta- D-Glucose Alpha-D-Glucose Differ in configuration of –OH group on anomeric carbon atom.

28. N-glycosides N-glycosides: when hydroxyl group on anomeric carbon of a sugar reacts with an amine N-glycoside is formed. N-glycosidic linkage is present in nucleotides, RNA and DNA. So, nucleotides, RNA and DNA are examples of N-glycosides.

30. Each nucleotide consists of a heterocyclic nitrogenous base, a pentose sugar and phosphate. - O P O O

31. Nucleoside - - - O O O Nucleoside monosphosphate (NMP) 5 - Base O O P O P P O CH2 O Nucleoside diphosphosphate (NDP) Nucleotides C O O O C 1 4 Nucleoside triphosphosphate (NTP) H H H 2 3 C C OH OH

32. BASE NUCLEOTIDE Adenine (A) Guanine (G) Cytosine (C) Thymine (T) Uracil (U) Adenosine Guanosine Cytidine Thymidine Uridine

33. Adenine Cytosine (C) NH2 NH2 C C 6 6 N N N 1 1 7 C CH 5 5 2 2 C C H 4 CH 4 8 CH C 3 3 9 O N N N H H Thymine (T) Guanine O O C C 6 HN 6 N 1 N 1 7 C-CH3 C 5 5 2 2 C C H 4 8 4 CH CH 3 C 3 9 O N N H N H

34. Base pairing • • • U • • • A T A • • • • • • G C G C • • • • • • C G C G • • • • • • A U A T • • • • • • A U A T • • • • • • U A T A • • • • • • G C G C • • • • • • U A T A • • • • • • G C G C • • • • • • C G C G • • • • • • U A T A

35. Hydrogen bonds

36. Thymine H H Adenine H H H C O N N H C H 7 C C 5 4 H C 6 C 8 5 C 6 N 3 9 1 N 1 C 4 2 N N 2 C 3 C N H

37. Cytosine N Guanine H H H O N C H C C H C C C N H N C N N C C N O H N H

38. 5‘ end 3‘ end 5‘ end 3‘ end

39. 5’ end O O O O CH2 CH2 CH2 CH2 O O O O O O O O P P P P - - - - O O O O Phosphate backbone Phosphodiester bonds Phosphodiester bonds O 3’ end

40. 3’ end 3 5 5 3 3 5 5’ end DNA Strands Are Antiparallel 5’ end 3’-carbon of the sugar is above 5’-carbon: The strand is said to run in 3’to 5’ direction. 5 O O O O CH2 CH2 CH2 CH2 O O O O O O O O P P P P 3 - - - - O O O O - - - - O O O O O O O O CH2 CH2 CH2 CH2 O O O O P P P P O O O O 5’-carbon of the sugar is above 3’-carbon: The strand is said to run in 5’to 3’ direction. 3’ end The two strands run in opposite direction.

41. Angstrom Unit= 0.1 nanometer

42. Types of DNA Predominates in vivo Predominates in DNA-RNA hydrinds The A form, which predominates in DNA-RNA hybrids, is similar to the B form , but is more compact. In the Z form, the bases of the two DNA strands are positioned toward the periphery of a left-handed helix. It is designated “Z” because, in each strand , a line connection the phosphates “zigs” and “zags”.

43. 有難う御座います