1. Learning Targets “I Can...” Define “codominance.” Complete a Punnett Square for genes that are codominant. Define “incomplete dominance” and give an example. Complete a Punnett Square for genes that show incomplete dominance. Describe how the environment can affect the expression of genes. Define a “sex-linked gene.” Complete a Punnett Square for genes that are sex-linked.

2. Special Inheritance Patterns

3. Introduction 1. Determine if the following traits are dominant or recessive???

4. Tongue Rolling

5. Ear Lobe Attachment

6. Widow’s Peak

7. PTC Tasting

8. Introduction 2. Many human traits are inherited in the typical dominant/recessive pattern.

9. Unusual Inheritance Patterns 1. Incomplete dominance: the dominant allele does not completely dominate over the recessive allele (Incomplete and Codominant Traits worksheet #1 and 6) SNAPDRAGONS

10. Unusual Inheritance Patterns RR ♂ x rr ♀ Red White Genotype frequency: Phenotype frequency:

11. Unusual Inheritance Patterns 2. Codominance: two dominant alleles are equal in dominance

12. Unusual Inheritance Patterns Example = Blood Types A and B are dominant; O is recessive Blood Type (Phenotype)Genotype A B O

13. Unusual Inheritance Patterns Genotype frequency: Phenotype frequency:

14. Unusual Inheritance Patterns 3. Polygenic Inheritance: many genes affect the same trait Example = skin color, eye color, hair color

15. Gene Linkage (Fruit Fly Lab Data) 1. Review of Metaphase I during MeiosisMetaphase 2. The LAW OF INDEPENDENT ASSORTMENT states that chromosomes line up independently of one another

16. Gene Linkage 3. Genetic variety of sex cells is increased

18. Gene Linkage 4. Genes located on different chromosomes line up independently. But what about genes on the same chromosome?? 5. Linked genes: genes located on the SAME chromosome; these traits tend to be inherited together EXAMPLES: Blonde hair and blue eyes, Red hair and freckles

19. Some dominant/recessive genes cause certain conditions (Human Genetic Disorder Worksheet #2 and 6) Examples 1. Dwarfism (dominant disorder) 2. Sickle Cell Anemia (recessive disorder)

20. Other conditions are caused by sex- linked genes (Sex-linked Traits Worksheet #3, 7, and 8) Examples 1. Hemophilia 2. Colorblindness

21. Other phenotypes are caused by sex- linked genes 3. Punnett squares for sex-linked traits: Hh, HH = normalhh = hemophilia X Y♂xX X ♀ Genotypic frequency: Phenotypic frequency:

22. Other phenotypes are caused by sex- linked genes 3. Punnett squares for sex-linked traits: Hh, HH = normalhh = hemophilia X Y♂xX X ♀ Genotypic frequency: Phenotypic frequency:

23. Other phenotypes are caused by sex- linked genes 4. Males are more likely to have sex-linked traits. Why? Males do not have an extra X chromosome to mask certain genes

24. Some traits are sex-influenced. This means that the gene is expressed differently in males and females. 1. Genes are on autosomes 2. Genes must be activated by hormones

25. References http://scienceprofonline.googlepages.com/Bentpinky.jpg/ Bentpinky-full.jpghttp://scienceprofonline.googlepages.com/Bentpinky.jpg/ Bentpinky-full.jpg http://www.scienceteacherprogram.org/images/Nakita08- 4.gifhttp://www.scienceteacherprogram.org/images/Nakita08- 4.gif http://www.ncrtec.org/tl/camp/gene/curl.jpg http://www.ncrtec.org/tl/camp/gene/widow.jpg http://learn.genetics.utah.edu/content/begin/traits/ptc/ima ges/DSC00100.jpghttp://learn.genetics.utah.edu/content/begin/traits/ptc/ima ges/DSC00100.jpg http://wiki.answers.com/Q/What_are_examples_of_domi nant_traitshttp://wiki.answers.com/Q/What_are_examples_of_domi nant_traits

26. References http://porpax.bio.miami.edu/~cmallery/150/mendel/c14x9 incomplete-dominance.jpghttp://porpax.bio.miami.edu/~cmallery/150/mendel/c14x9 incomplete-dominance.jpg http://creationwiki.org/pool/images/thumb/c/c6/Codomina nt.jpg/200px-Codominant.jpghttp://creationwiki.org/pool/images/thumb/c/c6/Codomina nt.jpg/200px-Codominant.jpg http://www.gsboc.co.uk/graphics/pupscolour.jpg http://www.myherbalwellbeing.com/article_images/littleg uy.jpghttp://www.myherbalwellbeing.com/article_images/littleg uy.jpg http://scanned.files.wordpress.com/2007/12/ssa.jpg http://www.humanillnesses.com/original/images/hdc_000 1_0002_0_img0129.jpghttp://www.humanillnesses.com/original/images/hdc_000 1_0002_0_img0129.jpg http://comps.fotosearch.com/comp/BDX/BDX107/color- blindness-test_~bxp26007.jpghttp://comps.fotosearch.com/comp/BDX/BDX107/color- blindness-test_~bxp26007.jpg