1. Heredity: Chapter 11.1

2. Heredity- the passing of traits from parents to offspring
Mendelian Genetics
11/7/2018
Gregor Mendel-
Father of Genetics
Heredity- the passing of traits from parents to offspring
Genetics- the branch of biology that focuses on heredity
G. Podgorski, Biol 1010

3. A little bit about Mendel
Austrian monk born 1822
Published work that became the basis for modern genetics in 1866
Studied at the University of Vienna to study math and science- learned how to experiment and use math to explain natural phenomena
Experimented with pea plants using quantitative analysis!

4. Traits Studied by Mendel

5. Why pea plants?
Reason #1: Many traits that have only 2 choices. Example: flowers can either be purple or white. Reason #2: Easy to control pollination- reproductive parts are enclosed within the flower. Mendel pollinated them himself! Reason #3: Pea plants are small, easy to grow, produce many offspring quickly!

6. Mendelian Genetics
11/7/2018
The Reality of “Round and Wrinkled” – Two Alternative Traits of the Seed Shape Character
Note that each of seed is a new individual of a different generation – seeds are not of the same generation as the plant that bears them.
G. Podgorski, Biol 1010

7. Mendel’s Model Organism – the Garden Pea
Mendelian Genetics
11/7/2018
Mendel’s Model Organism – the Garden Pea
G. Podgorski, Biol 1010

8. Monohybrid Cross Cross that involves one pair of contrasting traits.
Step 1:
Pea plants self pollinated ensuring true-breeding: all offspring would only display one form of a trait. Example- all purple flowers.
Called P generation (parent)
Step 2:
Cross pollinated P generation plants that had different traits. Offspring is F1 (fillial) Generation Example- one parent has green seeds, the other parent has yellow seeds

9. Mendel’s Monohybrid Cross – P to F1
Mendelian Genetics
11/7/2018
Mendel’s Monohybrid Cross – P to F1
A Punett square,
G. Podgorski, Biol 1010

10. Continued Crosses to the F2 (the grandchildren)
Mendelian Genetics
11/7/2018
Step 3:
Continued Crosses to the F2 (the grandchildren)
The green trait was not lost or altered, even though it disappeared in the F1.
One trait is dominant to the other in its expression.
The reappearance of the recessive
trait is ¼ of the F2
G. Podgorski, Biol 1010

11. F1 plants only showed 1 form of a trait
Mendelian Genetics
11/7/2018
Mendel’s Results
F1 plants only showed 1 form of a trait
The trait reappeared in the F2 generation in a ration of 3:1
For each of the 7 traits he found the same ratio!
G. Podgorski, Biol 1010

12. Calculating Mendel’s Ratios
Contrasting Traits
F2 Generation
Results
Fraction
Ratio
Flower Color
705 purple
224 white
705/224
3.15:1
Seed Color
6022 yellow
2001 green
Seed Shape
5474 round
1850 wrinkled
Pod Color
428 green
152 yellow
Pod Shape
882 round
299 constricted
Flower Position
651 axial
207 top
Plant Height
787 tall
277 dwarf

13. Assignments
Homework Assignment
Classroom Assignment
Design a newspaper ad that would have attracted someone like Mendel to purchase peas for genetic research. The ad should mention all of the benefits of pea plants (Pisum sativum) that make it useful for genetic research. Illustrated please
In your notebook, do 11.1 section review questions (1-3).
You may write in complete sentences or write the question.
This will be checked in at the beginning of class tomorrow, as a homework check.

14. Mendel’s Theory
Bio B
11.2
p. 164

15. Mendel’s Hypotheses: Foundation of Modern Genetics
Hypothesis #1:
For each inherited trait, an individual has 2 copies of the gene- one from each parent.
Hypothesis #2:
There are alternative versions of genes. These are called alleles. Example: allele for brown eyes, allele for blue eyes. Different versions of eye color.

16. Mendel’s Hypotheses: Foundation of Modern Genetics
Hypothesis #3:
When 2 different alleles occur together, one of them may be completely expressed, while the other may have no observable effect on the organism’s appearance.
dominant- expressed form of trait
recessive- trait that is not expressed

17. Mendel’s Hypotheses: Foundation of Modern Genetics
Hypothesis #4:
When gametes are formed, the alleles for each gene in an individual separate independently of one another. Thus, gametes carry only one allele for each inherited trait. When gametes unite during fertilization, each gamete contributes 1 allele.
(During meiosis)

18. Capital=Dominant Lower Case=Recessive
In pea plants:
The allele for violet flower color
(B) is dominant
The allele for white flower color
(b) is recessive

19. Terminology
Homozygous- If an individual has 2 alleles for a gene that are the same. Ex: blue eyes from mother, blue eyes from father=blue eyes Heterozygous- If an individual has 2 alleles that are different. Example: blue eyes from mother, brown eyes from father=brown eyes

20. Mendelian Genetics
11/7/2018
G. Podgorski, Biol 1010

21. Do you have dominant or recessive traits?
Dominant Trait
Recessive Trait
You? (Yes or No)
# of Dominant Classmates
# of Recessive Classmates
Cleft Chin
No cleft
Dimples
No dimples
Hair above knuckles
No hair
Freckles
No freckles

22. Genotype- set of alleles that individual has(codes)
Phenotype- physical appearance of a trait
Examples:
Ff Genotype: heterozygous for freckles
Ff Phenotype: has freckles
ff Genotype: homozygous for no freckles
ff Phenotype: doesn’t have freckles

23. Different Genotypes Can Produce the Same Phenotype
Mendelian Genetics
11/7/2018
Different Genotypes Can Produce the Same Phenotype
G. Podgorski, Biol 1010

24. Genotype vs. Phenotype Genotype Phenotype BB Homozygous dominant Bb
Heterozygous bb
Homozygous recessive

25. Law of Segregation
Organisms inherit two copies of each gene, one from each parent
Organisms donate only one copy of each gene in their gametes
Two copies of each gene segregate, or separate, during gamete formation

26. Principle of Segregation Demystified
Mendelian Genetics
11/7/2018
Principle of Segregation Demystified
Segregation
The principle of segregation is explained by the behavior of homologous chromosomes at meiosis.
G. Podgorski, Biol 1010

27. Segregation and Inheritance

28. Law of Independent Assortment
The inheritance of one trait does not affect the inheritance of any other trait
Example: eye color does not affect hair color or texture…

29. Assignment: Concept Map
Directions: Use the following words, connected by ideas, diagrams and lines to make a concept map.
Allele recessive
Homozygous heterozygous
Genotype phenotype
Law of segregation Law of
dominant independent assortment

30. Classwork: Notebook 11.2 Section Review Questions p. 318 (1-4)
Write question or answer in complete sentences

31. 8.3 Studying Heredity

32. A Punnett Square

33. CF - An Autosomal Recessive Trait

34. Punnett Square Carrier mother G g G GG Gg Carrier father g Gg gg
25%
50% g Gg gg
50%
25%
Child with CF

35. Autosomal Recessive: A Pedigree

36. Inheritance of an Autosomal Dominant Trait

37. Incomplete Dominance
In snapdragons red flower color is due to gene (R) and white to its corresponding allele (r). The heterozygous (Rr) condition results in pink flower color. This is referred to as “incomplete dominance.”