Name_______________________________________________

Lecture I: Mendel and Genetics

The Life of Gregor Mendel

Gregor Mendel was a _________________ He studied the sciences extensively and tendered the gardens of the Abbey, where he grew ___________.

1800s Conceptions of Inheritance

The _______________hypothesis: Every offspring has a blend of traits from its parents. This is wrong! If blending were the way things works, all __________________would be diluted over the

generations.

Why use Peas?

Peas are a great model organism to use for genetics becauseo Easy to __________and maintaino Easy to control ____________o Lots of _______________o Conspicuous traits (you can easily SEE and IDENTIFY them)o _______generation time

Mendel’s Experimental Method

1. Establish __________________________lines for particular traits. (For example, a COMPLETELY purple flower and COMPLETELY white flower)

2. Start crossing the lines (For example, cross the completely purple with completely white flowers)

3. Count the offspring that show particular traits

Mendel’s Data:

For any trait:

When 2 different lines are crossed, the first generation offspring (F1) only shows ________ of those traits.

When the F1 generation is crossed, ______traits are shows in the F2, and always in a ________ ratio!

Mendel’s Conclusions:

2 alleles!o Sexually reproducing organisms have 2 ____________(alleles) of any gene. o One is from mom, and one from ______

Dominant vs. Recessiveo When an organism has 2 different alleles, one (___________) will be expressed over the other

(_____________)

Genotype versus phenotype

Genotype refers to the specific alleles you carry for a specific gene. Phenotype refers to how those alleles are expressed, or what the trait

LOOKS like

Mendel’s Laws

Law of _________________________________o Only 1 allele for a trait goes into a _______________.o The segregation of alleles is a ____________process. o It is explained by the behavior of chromosomes during metaphase and anaphase of meiosis. o Alignment of chromosomes at the ________________________ is random.

Law of _________________________________________o Separate alleles for separate traits are passed _________________________ of each other. o This is also explained by the behavior of chromosomes during metaphase and _________________ of

meiosis. o Independent assortment can lead to combinations of traits in offspring that are _________________

from the traits of their parents.