1. Genetics

2. Mendelian Genetics
The passing of traits to the next generation is inheritance or heredity
Mendel- a monk who work with pea plants
Studied various traits in the peas

3. P, F1, and F2 Generations Parent generation - P generation
P x P - F1 generation or first filial generation
F1 x F1 - F2 generation or second filial generation

4. Genes in Pairs Allele- alternative form of a single gene
Dominant- able to mask
Recessive- is masked

5. Dominance Homozygous- two of the same alleles
Homozygous dominant (both dominant alleles)
Homozygous recessive (both recessive alleles)
Heterozygous- two different alleles
Genotype- an organisms pair of alleles
Phenotype- observable characteristic

6. Mendel’s Law of Segregation
Two alleles separate during meiosis
You have a chance of giving each allele

7. Monohybrid Cross
Cross a homozygous dominant plant and with a homozygous recessive plant
tall - dominant
dwarf - recessive
What do we expect the F1 and F2 Generations to look like?

8. F1 Generation

9. F2 Generation

10. Dihybrid Cross
Dihybrid Cross
Law of Independent Assortment
Simultaneous inheritance of 2 traits in the same organism
Must be on different chromosomes
Different chromosomes separate independently
Genes on different chromosomes separate independently

11. Cross two pea plants that are each hybrid for height (Tt) and also hybrid for pod color
(T-Tall and t- dwarf)
(Y=yellow and y=green)

12. What would happen?
What would happen if two genes were on the same chromosome?
(Circle one)
A. They sort independently of each other
B. They don’t sort independently of each other
Why

14. Complex Inheritance and Human Heredity Albinism
Can affect only the eyes, skin, or hair or be complete

16. Complex Inheritance and Human Heredity Sickle Cell Anemia
Autosomal Recessive
Red blood cells- sickle shape
heterozygotes have both normal and sickle-shaped cells
Heterozygotes protected from malaria
HH- no SCA/ get malaria
Hh- no SCA/ don’t get malaria
hh- afflicted with SCA
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Sickle cell

18. Pedigrees A diagram that traces inheritance
Can be used to predict genetic disorders in families

19. Incomplete Dominance
The heterozygote phenotype is a blend between the two homozygous phenotypes

20. Codominance
Both alleles are expressed at the same time

21. Complex Inheritance and Human Heredity
Epistasis
One allele can hide the effects of another allele
eebb
eeB_
E_bb
E_B_
No dark pigment present in fur
Dark pigment present in fur

22. Sex Determination (mammals)
Sex Chromosomes
XX- female
XY- Male
Sex chromosomes determine gender

23. Sex Linked Traits Located on the X chromosome Affects mostly males
Red Green Colorblindness
Hemophilia

24. Polygenic Traits Trait determined by many genes at many loci
Loci – locations on different chromosomes

25. Explain The Twins

26. Environmental Influences
Diet
Exercise
Sunlight and water
Temperature

27. Look at you: nice work, human!

28. Identical Twin Studies
Helps separate genetic contributions from environmental contributions
Traits that affect both twins are controlled partially by heredity
Traits expressed differently in identical twins are strongly influenced by the environment

29. Karyotype Studies
Picture of the chromosomes arranged in decreasing size
Chromosomes are stained
Look for abnormalities
Number of chromosomes
Missing parts to chromosomes

30. Male or Female?

31. See anything different?

32. Nondisjunction
During meiosis- sister chromatids fail to separate properly
Down syndrome
Sex Chromosomes

33. Down Syndrome
Trisomy #21 = 47
Turners Syndrome 46 – X=45 XO