CHARACTERISTICS OF LIFE

1. CHARACTERISTICS OF LIFE All Living Things reproduce!!!!! All Living Things Have DNA!!!!

3. Cladogram

4. WHY ARE WE ALL DIFFERENT? We all inherited different genes from our parents which determines our traits. Heredity – Passing on of traits from parents to offspring. 23 chromosomes from each parent.

5. Autosomal vs. Sex Chromosomes

6. ALL OF THE TRAITS THAT MENDEL STUDIED WERE AUTOSOMAL TRAITS. THAT IS WHY PEA PLANT WAS AN EASY STUDY. NO WEIRD TRAITS LIKE BLENDING!!!

7. Genes – Pieces of DNA that carry heredity instructions and are passed from parents. Traits – A distinguishing characteristic that is passed from parents to offspring. Genetics – Study of heredity(passing on of genes)

8. JOHANN Gregor Mendel was born July 22, 1822. Mendel became a friar at the Augustinian monastery in Brno, Czechoslovakia. From 1868 until his death, Mendel was the abbot of the monastery. Mendel was experimenting with flowers in the monastery's gardens. He wondered how traits were passed from parent to offspring. He studied the relations between parents and children with mathematical symbols.

9. Father of Modern Genetics • The first person to trace the characteristics of successive generations of a living thing • He was not a world-renowned scientist of his day. • Rather, he was an Augustinian monk who taught natural science to high school students.

10. Family • Second child of Anton and Rosine Mendel • They were farmers in Brunn • They couldn’t afford for him to attend college • Gregor Mendel then attended the Augustinian Monastery and became a monk

11. The Monastery Garden with the greenhouse whichGregor J. Mendel, O.S.A., had built in 1870. Its appearance before 1902.Courtesy of Villanova University Archives. Gregor J. Mendel, O.S.A., experimental garden (35x7 meters) in the grounds of the Augustinian Monastery in Old Brno.Its appearance before 1922. Courtesy of Villanova University Archives.

12. The Birth of the idea: Heredity • On a walk around the monastery, he found an atypical variety of an ornamental plant. • He took it and planted it next to the typical variety. • He grew their progeny side by side to see if there would be any approximation of the traits passed on to the next generation. • This experiment was "designed to support or to illustrate Lamarck's views concerning the influence of environment upon plants.“

13. GREGOR MENDAL He chose to study 7 different traits,only one at a time, so he could understand the mathematical results.(tall, flower color and position, pod color and shape, etc.) He learned that each plant had two genes for each trait. One from each parent.

14. He Argued!!!! • Parents pass on their offspring heritable traits(genes) SO two alleles for every trait. One from each parent!!! • Genes retain their individuality. There is no blending.

15. Why Did He Chose Peas? • Short generation times • Large number of offspring • Many different traits(varieties)

16. Why did Mendal work with peas? • Good choice for environment of monastery(food) • Network provided unusual varieties for testing- several traits. • Obligate self-pollination reproductive system • Crosses easy to document • Short life cycle • Easy to track he traits.

17. Character vs. trait • Character – heritable trait varies that varies among individual. Hair color, eye color, etc • Trait – Variant for a character – brown , black, blonde hair

18. Self- pollination Vs. Cross Pollination Self – pollination – plant pollinates itself. Peas do this. Mendel could decide on the test crosses. Cross pollination – Mendel crossed one plant with another by taking pollen from one type of plant and placing it on the other.

19. Mendel cross-pollinated pea plants • He cut away the male parts of one flower, then dusted it with pollen from another • He found that the plants' respective offspring retained the essential traits of the parents, and therefore were not influenced by the environment.

20. Mendel’s 4 Conclusion • There are alternative versions of gene that account for variations in inherited characters. Alleles: Alternate versions of a gene!!!

21. Mendel’s 4 Conclusion • For each character, an organism inherits two alleles. They can be the same or different. Homozygous – identical alleles Heterozygous – two different alleles.

22. Mendel’s 4 Conclusion • If the 2 alleles of an inherited pair differ, then one determines the organism’s appearance. It is called DOMINANT. Recessive – no affect on organism unless dominant is not present.

23. Mendel’s 4 conclusions • A sperm or egg carries only one allele for each inherited character because allele pairs separate from each other during gamete formation. • Law of segregation – Sperm and egg carries only one allele which separate during meiosis.

24. MENDAL’S EXPERIMENT PART 1- He bred a pure tall pea plant with a pure short pea plant. ALL the offspring were TALL. TT X tt = Tt PART 2 - F1 He crossed 2 of the offspring from the above cross. Results – 75% Tall 25% Short Tt X Tt = TT, Tt, tt

25. Mendelian genetics Character (heritable feature, i.e., fur color) Trait (variant for a character, i.e., brown) True-bred (all offspring of same variety) Hybrid (crossing of 2 different true-breds) P generation (parents) F1 generation (first filial generation)

27. Parent Generation F1 Generation F2 Generation, 3:1 ratio

28. Three Conclusions to His Research Principle of Dominance and Recessiveness One allele in a pair may mask the effect of the other Principle of Segregation The two alleles for a characteristic separate during the formation of eggs and sperm Principle of Independent Assortment The alleles for different characteristics are distributed to reproductive cells independently of the other genes on the chromosome.

29. Independent Assortment Chromosomes separate independently of each other This means all gametes will be different! B sperm B B Bb haploid (n) b b diploid (2n) b meiosis II meiosis I B F Bb Ff b f Bb Ff B f Bb Ff B F

30. Independent Assortment Genes for different traits can segretate independently during the formation of gametes without influencing eachother Question: How many gametes will be produced for the following allele arrangements? Remember: 2n (n = # of heterozygotes 1. RrYy 2. AaBbCCDd 3. MmNnOoPPQQRrssTtQq

31. Mendal’s Death • Died in 1884 of Nephritis(kidney inflammation). After his death, his papers were burnt by his abbott because they went against beliefs of the times. • His work was lost for 50 years!!

32. Genetic vocabulary……. • Punnett square: • Gene: point on a chromosome that controls the trait • Allele: an alternate form of a gene A or a • Homozygous: identical alleles for a character • Heterozygous: different alleles for a gene • Phenotype: physical traits • Genotype: genetic makeup • Testcross: breeding of a recessive homozygote X dominate phenotype (but unknown genotype)

33. Vocabulary • Diploid – Full number of chromosomes in a somatic cell • Haploid – Half number of chromosomes in a gamete.

34. Dominant and Recessive alleles Dominant alleles – upper-case a. homozygous dominant (BB – Brown eyes) Recessive alleles – lower case a. homozygous recessive (bb – blue eyes) b. Heterozygous (Bb – Brown eyes)

35. Dominant gene – Stronger of the two traits and masked(hides) the recessive trait. Recessive gene – Weaker trait. For these reasons, he is called the Father of Genetics.

36. GENETICS RULES GENETIC SYMBOLS Use symbols to represent different forms of a gene. Capital Letters – Represents dominant trait. Lower Case Letters – Represents recessive trait. Examples- B – Brown eyes b – blue eyes

37. GENETIC RULES Every organism has TWO forms of every gene. One from each parent. Each form is called an ALLELE. You could have got a blue eye gene from mom and a brown eye gene from dad. Examples – Bb, WW, gg, Rr An organism can have the same gene for the trait or they can have two different genes.

38. If the genes are the same, then they are called HOMOZYGOUS or purebred. Examples – aa(one antenna), AA(2 antenna), LL(different colored legs), ll(clear legs), TT(curly Tail), tt(straight tail) If the genes are different, then they are called HETEROZYGOUS or hybrid Examples – Aa(2 antenna), Ll(different color leg), Tt(curly tail)

39. Outward appearance Physical characteristics Examples: 1.Brown eyes 2.blue eyes Arrangement of genes that produces the phenotype Exmple: 1. TT, Tt 2. tt Phenotype vs. Genotype

40. GENETIC PROBABILITY Mendal crossed yellow and green pea plants and discovered that 1 out of 4 were green. He was using probability. Probability – The possibility or likelihood that a particular event will occur. Used to predict – the results of genetics crosses.

41. The squares contain the gene combinations that could occur in the cross. The genotype is the letter combination or gene combinations in the squares. Example – Tt, Aa, bb,or Ll The phenotype is the actual appearance of the organism. Example – curly tail, 2 antennas, 3 body Segments, different color legs

42. PUNNETT SQUARES A Punnett square is a special chart used to show the possible gene combinations in a cross between 2 organisms. Developed by an English genetists by the name of Reginald Punnett.

43. 5 Steps of Punnett Square • Determine the genotypes of parents. • Set up your Punnett Square. Dad’s genotype on top and Mom’s on side. • Fill in squares by combining sperm with egg. • Write out possible combos(genotype). • Determine phenotype ratio.

44. How does a Punnett Square Work? 1. Draw a square and divide it into 4 sections. 2. Write the gene pairs across the top of the box, then the other down the side 3. In each box, place the correct gene to see the possible combinations. Each square represents a 25% possibility of getting that trait.

45. PARTS OF A PUNNETT SQUARE Male Genes Female Genes Offspring Combinations

46. Cross between homozygous dominant and recessive. Tt Tt Tt Tt What are the percent of the offspring? What are the genotypes? What are the phenotypes?

47. Cross between two heterozygous parents. TT Tt tt Tt What are the percentages of offspring? What are the genotypes? What are the phenotypes?

48. Mathematical Computations In a Punnett Square where both parents are Hybrids the percents are listed below: 25% purebred(homozygous) black – BB 50% hybrid(heterozygous) black - Bb 25% purebred(homozygous) white - bb 50 % % of same genotype as parents - 75% % of same phenotype as parents -

49. What about 2 Traits? • BbTt x BbTt • The Gametes contain one of each of the alleles. (BT). • Each of the offspring contain four alleles exactly like the parents.(BbTt). • Notice the number of possible offspring has increased. • The phenotypic ratio is 9:3:3:1

50. Steps of Dihybrid Cross