1. Jodi Sheffield St. Rita Catholic School KERA Teacher Core 2003
Daddy’s Dimples
Jodi Sheffield
St. Rita Catholic School
KERA Teacher Core 2003

2. Unraveling the Chromosome
DNA
Adenine with Thymine
Cytosine with Guanine

3. Which process produces the cells used in sexual reproduction??
Mitosis vs Meiosis
Mitosis
Meiosis
Nuclear divisions 1 2
Number of cells produced 2 4
Identical
to parent
HAPLOID
One half
of parent
Genetic content
DIPLOID
Which process produces the cells used
in sexual reproduction??
Meiosis

5. Inherited Traits SurveyMe
Mom
Dad
Sib 1
Sib 2
Sib 3
Roll tongue
Widow’s
Peak
Attached Ear lobe
Hand
Clasp

6. http://www. genomenewsnetwork. org/resources/whats_a_genome/Chp1_2_1

8. Chromosome pair #3
Alleles – buddy genes on matched chromosomes
Locus – location of gene on the chromosome

9. Watch for these terms Dominant Recessive Phenotype Genotype Homozygous
Heterozygous
- the trait (allele) is expressed
- a trait that is only expressed when both alleles are the same
- the physical expression of traits
- the actual genetic composition
when the two alleles are the same
( purebred)
when the two alleles are different (hybrid)

10. Law of Random Segregation
What did Mendel show?
Each pair of parent factors (alleles) separate
Each parent passes only one factor (allele) to an offspring 
Which factor (allele) the parent passes is strictly chance
Law of Random Segregation

11. Law of Independent Assortment
What else did Mendel show?
Inheritance of separate traits stays separate
Law of Independent Assortment

12. And this means… Dominant Recessive Phenotype Genotype Homozygous
Heterozygous
- the trait (allele) is expressed
- a trait that is only expressed when both alleles are the same
- the physical expression of traits
- the actual genetic composition
- when the two alleles are the same
- when the two alleles are different

13. t short Using Mendel’s Know How
Dominant gene is usually represented by UPPERCASE
Recessive gene is usually represented by lowercase
T tall
t short

14. Putting alleles together....
T tall; dominant t short; recessive
Genotype Phenotype TT
homozygous
tall Tt
heterozygous
tall tt
homozygous
short

15. Let’s see some Random Segregation
Probablity - the science that determines chance
Punnett squares - probability diagram illustrating the possible offspring
Mama - Tt Dad - Tt
heterozygous; Tall
Mom T t
Dad T T T t T T t t t t

16. Interpreting the Punnett Square
mom T t
Dad T T T t T T t t t t
Genotypes TT Tt tt 1 : 2 : 1
Phenotypes
tall
short 3 : 1

17. Detached – D Attached - d
Family Traits
Earlobes
Detached – D Attached - d
Mom D D
Dad D d D d d D d D d d
Genotype Dd
Phenotype Detached

18. Can two parents with detached earlobes What is the probability?
have an attached kid?
Mom D d
Dad D D D d D D d d d d
Which genotype?
What is the probability?

19. A Few Things Beyond Brother Mendel Incomplete Dominance For example:
two different phenotypes produce offspring with a third phenotype that is a mixing of the parental traits
For example:
Red Flower +
White flower =
Pink flower

20. Phenotype (Blood Type)
Multiple Alleles
More than two alleles can be selected for the allelic pair (more than two choices)
For example: Blood type alleles – A,B,O
Genotype
Phenotype (Blood Type)
AA, AO A
BB, BO B OO O AB AB
Codominance
The trait (allele) is expressed with another dominant allele

21. Polygenic inheritance Polygenic inheritance
traits result from the interaction of several genes
For example:
Polygenic inheritance
traits result from the interaction of several genes
For example:
Skin color
Eye color
Height