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Human Genetics.

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Presentation on theme: "Human Genetics."— Presentation transcript:

1 Human Genetics

2 Pedigree Graphic representation of genetic inheritance Family tree

3 Pedigree

4 RecessiveTraits Attached earlobe Hitchhikers thumb
2nd toe larger than big toe

5 Recessive Disorders Cystic Fibrosis Abnormal amounts of mucus in lungs
Abnormal cilia in lungs Death by age 20 1 in 20 white Americans are carriers

6 Recessive Disorders Albinism Lack of pigmentation

7 Recessive Disorders Tay Sachs
Absence of enzyme that breaks down lipids Lipids build up in the brain causing brain damage Death by age 5 Amish and Ashkenazic Jews

8 Recessive Disorders Phenylketonuria-PKU
Absence of enzyme that breaks down phenylalanine Phenylalanine builds up causing brain damage Treated with diet

9 Recessive Pedigree

10 Recessive Pedigree

11 Dominant Traits Widows peak,free earlobes, dimples, cleft chin, polydactyly

12 Dominant Disorders Huntington’s Disease Fatal degeneration of brain
Onset of symptoms age 30-50 After having children

13 Dominant Pedigree

14 Dominant Disorders Achondroplasia Most common type of dwarfism
85% new mutations from normal parents Genotypes dd: Normal Dd: Dwarf DD does not survive

15 Sex- Linked Disorders Defective genes on X chromosome
Carrier mother passes defective gene to son Affected males pass defective gene to daughter (carrier) Affected females are rare

16 Sex- Linked Disorders Red-green colorblindness
Defective red and green light receptors in eye Ishihara-colour-test-plates/ what color blind people see

17 Colorblindness Genotypes
XRXR :Normal Female XRXr :Carrier Female XrXr :Colorblind Female XRY :Normal Male XrY :Colorblind Male No way to have a carrier male

18 Sex- Linked Disorders Hemophilia Absence of blood clotting enzyme
youtube: tainted bood pt 1 youtube: tainted bood pt 1 youtube: tainted bood pt 2

19 Royal Hemophilia Pedigree

20 Codominant Disorders Sickle-cell anemia
1 in 12 African Americans are carriers Genotypes HH Normal Hemoglobin HS both normal and defective hemoglobin Sickle-cell Trait Few or no symptoms

21 Codominant Disorders SS all hemoglobin is defective
Red blood cells become sickle shaped Carry less oxygen

22 Codominant Disorders Beneficial mutation
HS and SS are immune to malaria HH is not immune Youtube:evolution of sickle cell

23 Sickle-Cell Pedigree

24 Pedigree Practice The pedigree shows the inheritance of free earlobes and attached earlobes in five generations of a family. Attached earlobes are caused by a recessive allele (f).

25 Pedigree Practice

26 Pedigree Practice

27 Pedigree Practice

28 Pedigree Practice


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