2. Bell-ringer 3/3/16 1.What are linked genes? 2.Which two are more likely to always be linked and why? 3.GET OUT YOUR SEX-LINKED PRACTICE or PICK UP YOUR TURNED IN ONE OUT OF THE PILE

3. Section 12.2 Summary – pages 315 - 322 Patterns of inheritance that are explained by Mendel’s experiments are often referred to as “simple genetics”. However, many inheritance patterns are more COMPLEX than those studied by Mendel.

4. Section 12.2 Summary – pages 315 - 322 CO-DOMINANCE Black-colored feathers F White-colored feathers F BBWW B W Expressing both alleles equally BOTH alleles are Dominant

5. Section 12.3 Summary – pages 323 - 329 Co-dominance in Humans One example of this in humans is sickle-cell disease. Sickle-cell disease is a mutated gene that causes the red blood cells to be deformed.

6. Section 12.3 Summary – pages 323 - 329 In an individual who is homozygous for the sickle-cell allele, the oxygen-carrying protein hemoglobin differs by one amino acid from normal hemoglobin. Hb SS Co-dominance in Humans Individuals who are heterozygous for the allele produce both normal and sickled hemoglobin, an example of codominance. Hb AS Individuals homozygous for the normal hemoglobin allele have this genotype : Hb AA

7. Section 12.2 Summary – pages 315 - 322 For example: (Don‘t write this) A homozygous red-flowered plant (Pᴿ’ Pᴿ’) is crossed with…. a homozygous white-flowered plant (Pᵂ’ Pᵂ’), also dominant all of the first generation offspring will have pink flowers- they are only showing half of the red pigment, half of the white. INCOMPLETE DOMINANCE The allele expresses partial dominance Heterozygote has new intermediate pheontype BOTH alleles are Dominant, there are no recessives

8. P’ P’P’ P’P’ Law of Segregation? P’ ½ Red ½ White

9. Hair Texture – Is THOUGHT to be incomplete dominance. – Curly and Straight hair textures both show dominant patterns Other genes may be involved because there are varying degrees of ‘curly’ Heterozygote would be wavy hair (at varying degrees depending on curls)

10. Section 12.2 Summary – pages 315 - 322 An example is Blood Type. MULTIPLE ALLELES There are more than two possible dominant alleles and there are also recessive alleles FOR ONE TRAIT

11. Section 12.3 Summary – pages 323 - 329 Human Blood Types l A l A or l A i l B l B or l B i lA lBlA lB ii Genotypes Phenotypes A B AB O Multiple Alleles The ABO blood group is a classic example of a single gene that has multiple alleles in humans. Determining blood type is necessary before a person can receive a blood transfusion because the red blood cells of incompatible blood types could clump together, causing death. Human Blood Types Genotypes Phenotypes Human Blood Types Genotypes l A l A or l A i l B l B or l B i lA lBlA lB l A l A or l A i l B l B or l B i Al A l A or l A i l B l B or l B i Al A l A or l A i Bl B l B or l B i Al A l A or l A i

12. Blood Donation You cannot receive blood from just anyone. Because of this, donating blood is extremely helpful for doctors and hospitals. Type O– blood is considered the “universal donor” because it can be donated to people of any blood type. Type AB+ blood is considered the “universal recipient” because people with this type can receive any blood type.

13. Section 12.3 Summary – pages 323 - 329 The gene for blood type, gene l, codes for a molecule that attaches to the surface of red blood cells. Different blood types have different types of molecules on the outside of their red blood cells The ABO Blood Group The l A and l B alleles each code for a different molecule. Your immune system recognizes the red blood cells as belonging to you. If cells with a different surface molecule enter your body, your immune system will attack them.

14. Section 12.2 Summary – pages 315 - 322 POLYGENIC INHERITANCE POLY = MANY GENIC = GENES This means there can be an ARRAY of phenotypes. One trait (like skin color) is controlled by MANY genes Examples are height, hair color, eye color, and skin color.

15. Section 12.2 Summary – pages 315 - 322 Polygenic inheritance is CUMULATIVE and does NOT follow a dominant or recessive rule. POLYGENIC INHERITANCE Controlled by many genes in an individual For example: FACT: Height is controlled by 700 alleles. Let’s say…. Mom is of medium height: 350 tall and 350 short Dad is kinda tall: 560 tall and 140 short If you inherit 350 of mom’s tall genes….. and 350 of dad’s tall genes…. YOU ARE ONE TALL MAMMA JAMMA. Short Tall

17. Soooooo much more complicated Epigenetics: Environmental Influence: Other gene Influence: