1. Packet 8 Quiz: Monday 2/20 Packet 8 and 9 Test Friday 3/10
Important Dates for Packet 8 and 9:

2. Why do we look the way we do?
Intro to Genetics
Why do we look the way we do?
Packet 8- Mendelian Genetics
Pg. 1-2

3. We already know that if you look carefully at all 46 chromosomes, you would see that there are 2 pairs (1 of each pair comes from mom and the other from dad).
That means there are actually two chromosomes with instructions for each kind of trait (such as freckles, nose shape, etc.)
What is in our DNA?

4. Genes are segments of DNA or the places on the chromosomes that code for specific traits such as height, eye color, etc.
-Each chromosome is made up of hundreds to thousands of genes we inherit from our parents.
What is in our DNA?

5. Do your mom and dad look the same? –Probably not
Sometimes the two chromosomes in a pair don’t have the same instructions. The instructions from mom may be different from the ones you inherit from your dad.
Look at the chromosomes on the left:
7 traits have been identified in which the mom and dad have passed down different forms of the same gene (called alleles)
-Alleles are the result of differences in the G’s, C’s, A’s, and T’s in that stretch of DNA
Do your mom and dad look the same? –Probably not

6. Gregor Mendel ( ) was an Austrian monk that taught high school science and tended the garden of the monastery.
While he was not considered well known scientist of his time, today he is considered to be the father of modern genetics.
How do we know this?

7. Genetics is the branch of biology that studies heredity or the passing of traits from parents to offspring.
It took approximately 8 years for Mendel to gather enough data to report his theories of heredity.
What is heredity?

8. How do we know this? P1- Parental Generation
Using many generations (over 25,000 pea plants he was able to show how traits could be passed from parents to offspring, even traits that couldn’t be seen on the parent.
P1- Parental Generation
F1- 1st generation of offspring
F2- 2nd generation of offspring
How do we know this?

9. Mendel looked at the color of the flowers on his pea plants, the shape of the pea pods, and several other traits of the plants.
Mendel drew two conclusions from his experiments:
1. Inheritance is determined by traits that are passed from one generation to the next.
2. Some forms of a trait are dominant and others are recessive.
What did Mendel say?

10. We don’t show both of the traits we got from our parents, instead one shows up over the other.
The dominant allele is the trait that will show up even when paired with a different allele.
The recessive allele is a trait that can be hidden or masked when it is paired with a dominant allele.
If our parents give us two different versions of a trait, which one will show up?

11. How do we know what alleles we have?
Genotype- the genetic makeup of a trait represented by letters (FF, Ff, or ff; BB, Bb, or bb). Two letters should be used (one given by each parent).
-A capital letter is used to represent a dominant allele.
-A lower case letter is used to represent a recessive allele.
*Your genotype is the genes you have.
How do we know what alleles we have?

12. How do we know what alleles we have?
Phenotype- the appearance of a trait (freckles or no freckles, brown hair or blond hair).
*Your phenotype is your physical appearance.
How do we know what alleles we have?

13. How do we know what alleles we have?
Homozygous- when the pair of alleles are identical or the same form.
-Examples: TT or tt;
-remember: homo= same
Heterozygous- a pair of alleles that are not the same form… one is dominant and the other is recessive.
-Example: Tt
-Remember: hetero= different
How do we know what alleles we have?