Genetics & Taxonomics

1. Genetics & Taxonomics OR How I Learned To Stop Worrying And Love Genetic Engineering

2. History • Genetics is the study of how hereditary information is organized, expressed, and inherited • Procreation has been going on for two billion years

3. Gregor mendel • First explained the foundation principles of genetics in 1865, based on his experiments with pea plants • Not grasping the importance of the conclusions, No-one proceeded until 1900 when Mendel’s principals were rediscovered by three independent botanists

4. William Bateson • Coined the term genetics to describethe study of inherited characteristics

5. Ancient History • Humans recognized long ago that all forms of life have offspring after their own kind (resembling their parents) • Plant and animal breeding are among the earliest applications of scientific principals • It made agriculture possible, which made civilization possible.

6. “Let us never forget that the cultivation of the earth is the most important labor of man. When tillage begins, other arts follow. The farmers, therefore, are the founders of civilization.” • Daniel Webster

7. Modern history • In the early 20th century, scientists began applying experimental genetics to improve domesticated plants and animals • Although agricultural methods contributed greatly, the largest scale contributor to the Green Revolution was genetic improvement. • Crop yield increased sometimes fourfold in a mere 20 years

8. DNA • Deoxyribonucleic Acid (DNA) is the primary carrier of genetic information • It is a polymer made up of dideoxy neucleotide subunits • The structure is very similar in all living things • DNA was described about the same time that Mendel was conducting his experiments, but was not positively identified for it’s purpose until the 1950s

9. DNA representations

10. DNA molecule • DNA (and RNA) are nucleic acids • Nucleic because they make up most of a cell’s nucleus • Acid because it is acidic when dissolved in water

11. DNA molecule • Compared to most other molecules, it is of enormous size • With 46 separate DNA molecules in each cell, the length is 5 cm if stretched out straight. If all 46 were lined up they would measure over 2 meters (Fairbanks,Anderson 26)

12. DNA nucleotides • A DNA molecule is made up of four kinds of subunits called Nucleotides • Each nucleotide consists of a five carbon sugar (deoxyribose), with a nitrogenous base attached to one end and a phosphate group at the other.

13. DNA

14. DNA • The four Nitrogenous bases are • Thymine (t) • Cytosine (c) • Adenine (a) • Guanine (g) • Each nucleotide is refered to by its base name

15. DNA Bases • Cytosine and Thymine are called pyrimidines. • Similar to each other, they have one six member ring in the nitrogenous base

16. DNA Bases • Adenine and guanine are called the purines • Also similar in structure, each is composed of two rings, a six member ring attached to a five member ring

17. Pairing • In DNA, the structure is a double helix. • Each link of the helix has a base pair combination • Each combination can either be A-T,C-G,T-A or G-C • Cytosine only pairs with guanine and thymine only pairs with adenine

18. Amount of Data • A single human Diploid cell contains 6 billion base pairs • If a base pair has 4 possibilities it is 2 bits in hard drive space, and a byte is 8 bits, the hard drive space necessary to define Dr. Tey is: • 3 Gigabytes • 11k for Morgan

19. Strand Separation • As the strands separate, they must be allowed to unwind, or excess tension will build up and possibly form super coils • Enzymes called helicases unwind the DNA as the replication fork proceeds along the molecule • Enzymes called topoisomerases relieve the positive tension of unwinding

20. separation • The two separated strands must be chemically kept apart • Single-strand binding proteins (SSBs) do this

21. Synthesizing DNA • DNA polymerases make new DNA strands using a single strand of DNA as a template • DNA polymerase adds nucleotides only from the 5’ side towards the 3’ end • DNA polymerase does not initiate synthesis, therefore an RNA primer is required for initiation: initiated by primase

22. Replication driving force • The free nucleotides that are incorporated into DNA strands are in the tri-phosphate form. • As each nucleotide is added to the growing strand, phosphate groups are cleaved, releasing energy • This energy is what drives DNA synthesis

23. Gene • The word Gene was coined in 1909 by Wilhelm johannsen to describe the “fundamental unit of inheritance” • It is a section of DNA that encodes an RNA molecule

24. Central Dogma • The central dogma of molecular genetics is that the information in a gene is transcribed into RNA, and the information in RNA is then translated into Protein

25. Polyploidy • Diploidy - Pertaining to homologous chromosomes, where each chromosome number has a pair of chromosomes, such as the 23 pairs in humans totalling our 46 chromosome compliment. • Cells (and their owners) are polyploid if they contain more than two haploid (n) sets of chromosomes; that is, their chromosome number is some multiple of n greater than the 2n content of diploid cells. For example, triploid (3n) and tetraploid cell (4n) cells are polyploid.

26. Polyploidy • The chromosome content of most plants groups suggests that the basic angiosperm genome consists of the genes on 7-11 chromosomes. Domestic wheat, with its 42 chromosomes, is probably hexaploid (6n, where n (the ancestral haploid number) was 7.

27. Manipulating genes • Genetic Engineering is the making of something out of genes • Gene mapping lets engineers know which genes can be snipped out (spliced) into plant genes. • These plants can express the properties of those genes

28. Legal Issues • Market forces get genetic engineering companies to go too fast for safety • Superior plant qualities may cause another green revolution, overproduction, market destabilization. • Competition forcing poor farmers out of the business • GE food may cause health problems

29. Taxonomics • The science of biological classification that embodies the study of organic diversity and provides the tools to study the historical aspects of evolution • As currently practiced, Taxonomy has it’s beginning in the work of Sweedish botanist and naturalist Carolus Linaeus (Carl Von Linne) and his contemporaries in the mid-eighteenth century

30. Essential activities of systematics has changed little over the last 250 years • The recognition of basic units in nature, which are usually called species • Due to improvement in understanding of the mechanism of inheritance, taxonomy has improved • But with more than 2 million species of plants and animals, they are often recognized on the basis of morphological and other observable characteristics.

31. The classification of these species in a hierarchic scheme • Early taxonomists like Linaeus were less motivated to investigate the forces that produced organic diversity than they were to describe the product themselves • With the Darwinists, evolutionary process, rather than divine creation explained observable relationships.

32. It still took 100 years for the development of methods for deducing relationships.

33. The placement of information about species and their classification into a wider context.