1.  11–1The Work of Gregor Mendel A.Gregor Mendel’s Peas B.Genes and Dominance C.Segregation 1.The F 1 Cross 2.Explaining the F 1 Cross Section 11-1 Section Outline

2. This is the branch of biology which studies heredity. White Tiger - - - - This type of tiger can have yellow parents. How can that happen? Daschuand, Collie, Great Dane, Poodle, Greyhound, Labrador, Terrier, Pit-bull WWWWhat are some inherited traits for some dog breeds? (Physical and behavior) HHHHow do you keep producing a pure breed? TTTTerms -alleles, hybrid, genes, purebred, traits Genetics

3. 11-1 1. Discuss who Gregor Mendel was and discuss his contribution to biology. 2. What characteristics did he study? 3. What is the P 1, F 1, F 2 generation? 4. What are pure plants? Give one example of self-pollination and cross pollination. 5. How did Mendel determine which of each pair of traits was the dominant trait and which was recessive? 6. Although Tall plants appear to be tall, could they be considered “pure” for the tall trait? Why or why not?

4. What is the F 1 generation? What else did Mendel do? This generation showed only one trait from the parents that were crossed ( green pod, no yellow pod). He allowed these to self-pollinate. This is called the F 2 generation. Results of this pollination showed 3/4 were green and only 1/4 were yellow. The yellow pod trait had appeared to be lost in the F 1 generation, actually reappeared in the F 2 generation.  How did Mendel determine which of each pair of traits was the dominant trait and which was recessive?  Although Tall plants appear to be tall, could they be considered “pure” for the tall trait? Why or why not?

5. GREGOR MENDEL Mendel was a monk who lived during the mid 1800’s in Austria. He was great in math and was a gardener at the monastery. He noticed various things about pea plants and their characteristics. He studied seven characteristics of pea plants and noticed what we today call inheritance or the passing of traits by heredity. Mendel’s experiments: 1. He studied each characteristic individually. He took “pure” plants for a trait and allowed them to go through self-pollination. What are pure plants? What is self-pollination? The offspring which resulted from this cross in known at the parental generation or P 1 generation. ( parent self-pollinated) 2. Mendel then crossed the P 1 generation of opposite traits by cross- pollinating them (yellow pods with green pods).

6. P Generation F 1 Generation F 2 Generation TallShortTall Short Section 11-1 Principles of Dominance

7. Seed Shape Flower Position Seed Coat Color Seed Color Pod Color Plant Height Pod Shape Round Wrinkled Round Yellow Green Gray White Smooth Constricted Green Yellow Axial Terminal Tall Short YellowGraySmoothGreenAxialTall Section 11-1 Figure 11-3 Mendel’s Seven F 1 Crosses on Pea Plants

8. Conclusions of Mendel 1. Principle of dominance an Recessiveness One factor of a pair of alleles may mask the appearance of another. (Ex: blond hair is recessive to dark hair) 2. Principle of Segregation The two factors for a characteristic separate, during the formation of eggs and sperm. (B - Brown, b - blue) Which allele did you get? 3. Principle of Independent Assortment- Factors for different characteristics are distributed independently to sex cells. (curly fur /size of dog or tall plant /wrinkled seeds) (curly fur /size of dog or tall plant /wrinkled seeds)  Mendel’s most important decision was to study just a few isolated traits of the pea plants.

9. Section 11-1 What do the numbers mean? What is the ratio of dominant to recessive? Parents Long stems  short stems Red flowers  white flowers Green pods  yellow pods Round seeds  wrinkled seeds Yellow seeds  green seeds First Generation All long All red All green All round All yellow Second Generation 787 long: 277 short 705 red: 224 white 428 green: 152 yellow 5474 round: 1850 wrinkled 6022 yellow: 2001 green

10.  11–2Probability and Punnett Squares A.Genetics and Probability B.Punnett Squares C.Probability and Segregation D.Probabilities Predict Averages Section 11-2 Section Outline Go to Section:

11. Section 11-2 Tt X Tt Cross

12. Section 11-2 Tt X Tt Cross Go to Section:

13. Height in Humans  Height in pea plants is controlled by one of two alleles; the allele for a tall plant is the dominant allele, while the allele for a short plant is the recessive one.  What about people?  Are the factors that determine height more complicated in humans?  Can you only be tall or short? Section 11-3 Interest Grabber Go to Section:

14.  11–3Exploring Mendelian Genetics A.Independent Assortment 1.The Two-Factor Cross: F 1 2. The Two-Factor Cross: F 2 B.A Summary of Mendel’s Principles C.Beyond Dominant and Recessive Alleles 1.Incomplete Dominance 2.Codominance 3.Multiple Alleles 4. Polygenic Traits D.Applying Mendel’s Principles

15. *Gene interactions(Recessive vs. Dominant) recessive genes do not produce the enzyme for a trait to be demonstrated. Incomplete dominance - hybrids are intermediates of the parents. (Ex red x white = pink). The recessive allele can not make any pigment at all so less pigment shows up (diagram) Codominance - both differing alleles of a gene are expressed at the same time. There is no dominance of one over the other. (Ex: roan cattle are a hybrid of a Red and White cross R xR’) Polygenic Inheritance - traits are controlled by two or more genes. (Ex Lab retrievers have two separate genes which determine coat color) Multiple alleles - numerous versions of a gene are possible. (eye color, blood type, etc.)diagram

16. concluded that which is called the Gregor Mendel Law of Dominance Law of Segregation Pea plants “Factors” determine traits Some alleles are dominant, and some alleles are recessive Alleles are separated during gamete formation Section 11-3 Concept Map Go to Section: experimente d with

17. Section 11-3 Figure 11-11 Incomplete Dominance in Four O’Clock Flowers Go to Section:

19. Section 11-3 Figure 11-10 Independent Assortment in Peas Go to Section:

20.  11–5Linkage and Gene Maps A.Gene Linkage B.Gene Maps Section 11-5 Section Outline Go to Section:

21. What are some products that often come in packages containing several different colors and flavors? What happens if you want only one flavor? What else do you get besides the color or flavor you want? Linkage groups- these are “packages” of genes that tend to be inherited together. There is one linkage groups for every homologous pair of chromosomes. *A human cell has about 100 000 different genes attached in a single line on each chromosome. Crossing Over If genes for body color and wing size are linked, why aren’t they linked all the time? Sections of the chromosomes can cross, break and reattach during Meiosis I. (see diagram) Recombinants - individuals with new combinations of genes. It is believed that 2-3 cross-overs occurs on each pair of human homologs in sex cells.

23. Punnett Square - name after Reginald Punnett who studied genetics in the 1900’s. Sutton - (1902) His Chromosome theory of heredity states that genes are located on chromosomes and each occupies a certain place. Each chromosome contains a form of the gene called an allele. There can be two or more alleles for each gene. (see diagram) Linked genes - they are found on the same chromosome and do not undergo independent assortment. Discovered in fruit flies by Thomas Hunt Morgan.

24. What if there was no crossing-over in any organism? Gene Mapping Distance between genes (alleles) determines how often crossing over occurs. The farther apart- the more likely genes are to cross-over. This distance helps to “map” a chromosome and tell the probable place to find a certain gene on the chromosome. Sex linkage - There is an exception to the rule that all chromosomes has a matching homolog. This was discovered by Nettie Stevens (1905) in her study of meal worm chromosomes. The Y chrom is much smaller and a different shape than the X chrom. Her promising scientific career was cut short by cancer at age 41. (FYI) Genes located on one of the sex chromosomes is said to be sex linked. How is the sex of offspring determined? (Review)

25. Crossing-Over Go to Section:

26. Crossing-Over Go to Section:

27. Crossing-Over Go to Section:

29. Exact location on chromosomesChromosome 2 Section 11-5 Figure 11-19 Gene Map of the Fruit Fly Go to Section:

30. Earth Country State City People Cell Chromosome Chromosome fragment Gene Nucleotide base pairs Section 11-5 Comparative Scale of a Gene Map Go to Section: Mapping of Earth’s Features Mapping of Cells, Chromosomes, and Genes