1. Fig. 14-1

2. Answer the following with your partner 1. What does a “pure strain” or true-breeder” mean? Think about Mendel’s pea experiments. 2. What is a monohybrid cross? What are the genotypic and phenotypic ratios? 3. What is a dihybrid cross? Phenotypic ratios? 4. Explain incomplete dominance.

3. Fig. 14-2a Stamens Carpel Parental generation (P) TECHNIQUE 1 2 3 4

4. Fig. 14-2b First filial gener- ation offspring (F 1 ) RESULTS 5

5. Fig. 14-3-3 EXPERIMENT P Generation (true-breeding parents) Purple flowers White flowers  F 1 Generation (hybrids) All plants had purple flowers F 2 Generation 705 purple-flowered plants 224 white-flowered plants

6. Fig. 14-4 Allele for purple flowers Homologous pair of chromosomes Locus for flower-color gene Allele for white flowers

7. Fig. 14-6 Phenotype Purple 3 Genotype 1 White Ratio 3:1 (homozygous) (heterozygous) PP Pp pp Ratio 1:2:1 1 1 2

8. Fig. 14-7 TECHNIQUE RESULTS Dominant phenotype, unknown genotype: PP or Pp? Predictions Recessive phenotype, known genotype: pp  If PPIf Pp or Sperm ppp p P P P p Eggs Pp pp or All offspring purple 1 / 2 offspring purple and 1 / 2 offspring white Test cross

9. Degrees of Dominance Complete dominance occurs when phenotypes of the heterozygote and dominant homozygote are identical In incomplete dominance, the phenotype of F 1 hybrids is somewhere between the phenotypes of the two parental varieties In codominance, two dominant alleles affect the phenotype in separate, distinguishable ways Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

10. Fig. 14-10-3 Red P Generation Gametes White CRCRCRCR CWCWCWCW CRCR CWCW F 1 Generation Pink CRCWCRCW CRCR CWCW Gametes 1/21/2 1/21/2 F 2 Generation Sperm Eggs CRCR CRCR CWCW CWCW CRCRCRCR CRCWCRCW CRCWCRCW CWCWCWCW 1/21/2 1/21/2 1/21/2 1/21/2 Incomplete dominance

11. Fig. 14-5-3 P Generation Appearance: Genetic makeup: Gametes: Purple flowers White flowers PP P pp p F 1 Generation Gametes: Genetic makeup: Appearance: Purple flowers Pp P p 1/21/2 1/21/2 F 2 Generation Sperm Eggs P P PPPp p p pp 31

12. Fig. 14-9 Rr  Segregation of alleles into eggs Sperm R R R R R R r r r r r r 1/21/2 1/21/2 1/21/2 1/21/2 Segregation of alleles into sperm Eggs 1/41/4 1/41/4 1/41/4 1/41/4

14. Gene Linkage: Drosophilia melanogaster –has only 4 pairs of chromosomes. Therefore must have large # of genes on each. Dr. Thomas Hunt Morgan (1910) mapped these genes. Genes stay together during process of meiosis unless crossing over occurs. This does not support Mendel’s Principle of Independent Assortment Chromosome #2 has genes controlling Eye color, wing type, body color, etc. Crosses involving linked genes do not give The same phenotypic ratio as unlinked.

15. Morgan’s Choice of Experimental Organism Several characteristics make fruit flies a convenient organism for genetic studies: They breed at a high rate A generation can be bred every two weeks They have only four pairs of chromosomes Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

16. Fig. 14-8a EXPERIMENT P Generation F 1 Generation Predictions Gametes Hypothesis of dependent assortment YYRR yyrr YR yr YyRr  Hypothesis of independent assortment or Predicted offspring of F 2 generation Sperm YR yr Yr YR yR Yr yR yr YR YYRR YyRr YYRr YyRR YYrr Yyrr yyRR yyRr yyrr Phenotypic ratio 3:1 Eggs Phenotypic ratio 9:3:3:1 1/21/2 1/21/2 1/21/2 1/21/2 1/41/4 yr 1/41/4 1/41/4 1/41/4 1/41/4 1/41/4 1/41/4 1/41/4 1/41/4 3/43/4 9 / 16 3 / 16 1 / 16

17. Write a paragraph explaining the connection between Mendel’s Principles of Segregation and Independent Assortment and meiosis. Turn in when completed.

18. Rh factor is a protein called an antigen on RBC An antigen is any substance that the body considers "foreign" and thus stimulates the body to produce antibodies against it. Rh factor, like the blood types A, B, and O, is inherited from one's parents. A simple blood test can determine blood type, including the presence of the Rh factor. About 85 percent of white Americans and 95 percent of African Americans have the Rh factor and are known as Rh-positive. Those without the Rh factor are Rh-negative.

21. Correlating Behavior of a Gene’s Alleles with Behavior of a Chromosome Pair In one experiment, Morgan mated male flies with white eyes (mutant) with female flies with red eyes (wild type) The F 1 generation all had red eyes The F 2 generation showed the 3:1 red:white eye ratio, but only males had white eyes Morgan determined that the white-eyed mutant allele must be located on the X chromosome Morgan’s finding supported the chromosome theory of inheritance Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

22. Fig. 14-15b 1st generation (grandparents) 2nd generation (parents, aunts, and uncles) 3rd generation (two sisters) Widow’s peakNo widow’s peak (a) Is a widow’s peak a dominant or recessive trait? Wwww Ww ww Ww wwWW Ww or

23. Fig. 14-15c Attached earlobe 1st generation (grandparents) 2nd generation (parents, aunts, and uncles) 3rd generation (two sisters) Free earlobe (b) Is an attached earlobe a dominant or recessive trait? Ff ffFf ff FFor FF Ff

24. The European Royal Family back

25. Photo: www.freewebs.com/georgeromanov/Foto%201913.jpg

26. The Behavior of Recessive Alleles Recessively inherited disorders show up only in individuals homozygous for the allele Carriers are heterozygous individuals who carry the recessive allele but are phenotypically normal (i.e., pigmented) Albinism is a recessive condition characterized by a lack of pigmentation in skin and hair Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

28. Inheritance of Sex-Linked Genes The sex chromosomes have genes for many characters unrelated to sex A gene located on either sex chromosome is called a sex-linked gene In humans, sex-linked usually refers to a gene on the larger X chromosome Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

29. Sex-linked genes follow specific patterns of inheritance For a recessive sex-linked trait to be expressed A female needs two copies of the allele A male needs only one copy of the allele Sex-linked recessive disorders are much more common in males than in females Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

30. Fig. 15-7 (a)(b) (c) XNXNXNXN XnYXnY XNXnXNXn   XNYXNY XNXnXNXn  XnYXnY Y XnXn Sperm Y XNXN Y XnXn XNXnXNXn Eggs XNXN XNXN XNXnXNXn XNYXNY XNYXNY XNXN XnXn XNXNXNXN XnXNXnXN XNYXNY XnYXnY XNXN XnXn XNXnXNXn XnXnXnXn XNYXNY XnYXnY

31. Fig. 14-11 IAIA IBIB i A B none (a) The three alleles for the ABO blood groups and their associated carbohydrates Allele Carbohydrate Genotype Red blood cell appearance Phenotype (blood group) I A I A or I A i A B I B I B or I B i IAIBIAIB AB iiO (b) Blood group genotypes and phenotypes

32. The European Royal Family back

33. The Behavior of Recessive Alleles Recessively inherited disorders show up only in individuals homozygous for the allele Carriers are heterozygous individuals who carry the recessive allele but are phenotypically normal (i.e., pigmented) Albinism is a recessive condition characterized by a lack of pigmentation in skin and hair Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings

34. Fig. 14-16 Parents Normal Sperm Eggs Normal (carrier) Normal (carrier) Albino Aa A A AA Aa a aa a 

35. Fig. 14-17 Eggs Parents Dwarf Normal Dwarf Sperm Dd  dd d D Dd dd Dd d d

36. Fig. 14-UN2 Degree of dominance Complete dominance of one allele Incomplete dominance of either allele Codominance Description Heterozygous phenotype same as that of homo- zygous dominant Heterozygous phenotype intermediate between the two homozygous phenotypes Heterozygotes: Both phenotypes expressed Multiple alleles Pleiotropy In the whole population, some genes have more than two alleles One gene is able to affect multiple phenotypic characters CRCRCRCR CRCWCRCW CWCWCWCW IAIBIAIB I A, I B, i ABO blood group alleles Sickle-cell disease PP Pp Example