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2 Incomplete dominance Intermediate in phenotype

3 Blood type co-dominance 4 6

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6 Genetics – Dominant Traits, Recessive

7 Hitchhiker’s Thumb Dominant allele – hiker’s thumb Recessive – straight thumb

8 Tongue Rolling Ability to Roll is dominant Inability to roll is recessive

9 Mid-Digital Hair Presence of hair results from dominant allele Absence results from recessive allele

10 Widows Peak – a dominant trait (straight hairlines are recessive

11 Pedigree analysis

12 Genetic Disorders

13 (Trisomy 21) = Down’s syndrome results from 3 copies of chromosome pair 21

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15 Sickle Cell Anemia Occurs most often in people of African descent Is recessive on chromosome #11 Abnormal blood protein changes shape of blood cell Misshaped and carries less oxygen Cells get less oxygen and suffocate with this disorder Misshaped cells cause blocked capillaries and arteries - often strokes

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17 There is a interesting thing about sickle cell anemia. People who carry the tendency to have sickle cell anemia are less likely to die from malaria. Sometimes what is bad in one situation helps out in another.

18 MalariaMalaria is a disease caused by a parasite that likes to set up housekeeping in the red cells. This parasite is carried by the Anopheles mosquito. Anopheles

19 Albinism Lack of pigmentation Often sickly, tired and/or weak Eyes lack pigment and appear red due to blood vessels

20 Phenylketonuria (PKU) Enzyme missing to break down the amino acid phenylalanine Child usually does not survive long 

21 Tay Sachs Disease Harmful fatty acids produced in brain of a developing child Enzymes not produced to reduce levels Nerve cells are injured by the fatty acids Characteristic cherry red spot in the eye develops No cure Death occurs by age 5 on average 

22 Colorblindness If Mom has it, all her sons will and girls have a 50:50 chance of getting it Punnett Square XcXcXcXc XXc X YXcYXcYXcYXcY All daughters are carriers, but with one working X, they do not show colorblineness All sons colorblind – boo hoo, sniff, sniff Colorblind Mom: Xc Xc Okay Dad: XY

23 Take the Test

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28 Colorblindness Gene is located on the X-Chromosome. Use of a Pedigree to Track Transmission

29 Testing for Genetic Disorders Karyotyping – picturing human chromosomes

30 Fetal Diagnosis for Genetic Problems – Amniocentesis & the Needle of Doom

31 Overall lessons: 1.Your overall phenotype is controlled thousands of separated genes. 2.Some alleles are co-dominant so there can be more than two phenotypes per gene. 3.Genetics is never simple! – it becomes complicated when more than one gene is involved in producing a phenotype (Green eyes for ex.) 4.Pedigree analysis can help one determine human genotypes. 5.Harmful recessive genetic traits can persist in the population through carriers 6.Genetic testing will become more widespread. 7.Not all genetically-caused disorders are inherited. Some are caused by mutation of your genes by chemicals or radiation. Overall Lessons about Genetics