Have Graphs from Lab out and ready to b e checked

1. Have Graphs from Lab out and ready to be checked

2. Genetics

3. Definitions • Heredity- passing of characters from parents to offspring • Genetics- branch of biology that focuses on heredity • Monohybrid cross-is a cross that involves one pair of contrasting traits • P generation- first two individuals that are crossed • F₁ generation- is the offspring of the P generation • F₂ generation- is the offspring of the F₁ generation

4. Genetics • Explains the stability of inheritance and also variations between offspring from one generation to the next • How long has Genetics been around?

5. How Old is Genetics • From the first time man planted plants for food, to the taming of animals • Genetics was originally thought of as the Blending concept • What changed and what was the Blending concept?

6. Blending Concept • Before the late 19th Century • Offspring’s genetic makeup was intermediate to that of its parents • Ex. Red flower crossed with white flower would yield nothing but pink flowers • This could not explain why for example why pink flower plants produced both red and white offspring This did not help Darwin explain how diverse forms evolve

7. What Changed? • Gregor Mendel • Austrian monk • One of the first to use mathematics in experiments • Particulate Theory • 1860’s Garden Pea experiment • Considered the Father of Genetics

8. Particulate Theory • Based on the existence of minute particles or hereditary units • These units are now called Genes • Two laws came from this theory • Law of segregation • Law of independent assortment

9. Garden Pea (Pisumsativum) • Why was the Garden pea chosen • Many easy to identify traits • Easy to control pollination • Easy to maintain • Short generation time • Lead to obtaining True-breeding plants

10. True-Breeding • What is True-Breeding? • It is when the offspring are the same and exactly like the parents

12. Experiment • Started by choosing varieties that only differed by one trait • Like tall to short plants • Generations • P-parents (true-Breeding) • F1 is offspring • After first cross all offspring resembled tall parents • What did this mean

13. Experiment • F2 generation was ¾ were tall and ¼ was short • This lead to Mendel to deduce tall dominate over short • This is referred to as a Monohybrid cross • Cross of a single trait • 3:1 ratio in F2 generation • This explains the Law of Segregation

14. Monohybrid Cross • Aa to Aa

15. Monohybrid Cross • Cross between Aa to Aa • Results 3:1

16. Experiment • Law of Segregation • F1 parents contained two separate copies of each hereditary factor, one dominate and the other recessive • Factors separated when the gametes were formed, and each gamete carried only one copy of each factor • Random fusion of all possible gametes occurred upon fertilization

17. Definitions • Locus- location of a pair of chromosomes • Alleles- alternative versions of same gene • Dominant –fully functional protein • Recessive-protein with little or no function

18. Definitions • Homozygous-two identical alleles • Heterozygous-two different alleles • Genotype –alleles an individual receives at fertilization(DNA) • Phenotype-physical appearance of the individual (protein) • The protein that makes the phenotype is produced by the DNA that makes up the Genotype

19. Mendel’s Second experiment • Two true-breeding plants with two different traits • Ex. Tall with green pods and short with yellow pods • This is know as a dihybrid cross (9:3:3:1 phenotypic ratio) • Because the plants are hybrid in two ways

20. Experiment 2 • Two possible out comes • If Dominant factors always segregate into F1 and recessive always stay together than there will be two phenotypes in F2 plants • If the four factors segregate into F1 gametes independently, then there would be four phenotypes among the F2 plants • Tall Green, Tall yellow, short green, short yellow

21. Experiment 2 • Law of Independent Assortment • Each pair of factors segregate/assort independently of the other pair • All possible combinations of factors can occur in the gametes • Note the law of independent assortment applies only to alleles on different chromosomes

22. Question • Dihybrid cross AaBb with AaBb

23. Question • 9 with dominate AB 3With Ab 3with aB and 1 with ab

24. Review

25. Inheritance of traits • Pedigree- family history that shows how a trait is inherited over several generations • Sex-linked gene’s- allele is located only on the X or Y chromosomes • Incomplete dominance- when a individual displays a phenotype that is intermediate between two parents • Multiple alleles- genes with three or more alleles • Codominance- when two dominant alleles are expressed at the same time • Crossing over- the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes

26. Pedigree

27. Pedigree

28. Sex-linked gene’s • Most sex-linked genes are carried on the X chromosome • Who is most likely to exhibit these conditions? • Why are males more likely to exhibit a sex-linked condition? • Ex. Red-Green color blindness, Male pattern baldness, hemophilia

29. Incomplete Dominance • Predict the out come of a true breeding red snapdragon with a true breeding white snapdragon in incomplete dominance

30. Multiple Alleles • Ex. Blood types • Determined by the three alleles (Iᴬ, Iᴮ, i)

31. Codominance • Codominance and Incomplete dominance deferrer because both traits are displayed in codominance • Ex. Type AB blood

32. Genetic disorders • Sickle Cell Anemia • Cystic Fibrosis • Hemophilia • Huntington’s Disease • Abnormalities in Karyotypes • Trisomy • Monsomy

33. Abnormalities in Karyotypes • Monosomy – chromosome having no homology, especially unpaired X chromosome • Turner’s syndrome- missing one sex chromosome • Lethal • Trisomy- three instances of a particular chromosome, instead of the usually two • Ex. Down syndrome there is an extra chromosome 21 • Klinfelter’s syndrome were there is XXY sex chromosome

34. Sickle Cell Anemia • Recessive genetic disorder occurs in 1out of 500 births (mostly African American) • Caused by mutated allele that produces a defective form of the protein hemoglobin • Side effects- red blood cells are sickle shaped, rupture easily, tend to get stuck in blood vessels • The recessive allele that causes sickle-shaped cells also helps protect the cells of heterozygous individuals from the effects of malaria

35. Sickle Cell Anemia • malariais a disease caused by a parasitic protozoan that invades red blood cells

36. Cystic Fibrosis • Most common fatal, hereditary, recessive disorder among Caucasians • Side effects- airways of lungs become clogged with thick mucus, and ducts of the liver and pancreas become blocked • Treatments can relieve some of symptoms, but there is no know cure

37. Cystic Fibrosis • 1 in 25 Caucasians has at least one copy of a defective gene that makes a protein necessary to move chloride into and out of cells about 1 in 2500 infants in US is homozygous for the cf allele

38. Hemophilia • Recessive genetic disorder in hemophilia • Impairs the blood’s ability to clot • Sex-linked trait • Over a dozen genes code for the protein involved in blood clotting • Mutation on 1 of these genes on the X chromosome causes hemophilia

39. Hemophilia • Most common in Males • 1 in 10,000

40. Huntington’s Disease • Genetic disorder caused by a Dominant allele located on an autosome • Symptoms- mild forgetfulness and irritability appears in thirties to forties • Over time causes loss of muscle control, physical spasms, severe mental illness, and eventually death • 1 in 10,000