NAME:______
Introduction to Genetics Guided Notes
1. Basic Terms
Heredity:
Genetics:
Traits:
Gametes:
Fertilization:
2. The Work of GREGOR MENDEL
Who is Gregor Mendel?
An Austrian Monk who carried out the first important studies on ______. Mendel carried out experiments using the ______. Mendel was the 1st person to predict how traits are transferred from one generation to the next.
3. Mendel’s First Cross
His first cross was a ______(“mono” meaning ______thus monohybrid means a cross of ______)
The first trait Mendel wanted to analyze was ______. To do this he selected a ______and a ______. The plants Mendel selected were known as ______, because they came from generations of plants that were the same height (all tall or all short). Thus this cross is called a ______because it is done with two purebred organisms.
Using his cross pollination, Mendel performed the following genetic cross:
Cross #1: Tall Pea Plant x Short Pea Plant à Parent Generation (______)
Results: ______Pea Plants à First offspring (______)
Next he took all of the tall pea plants from the first generation and crossed them.
Cross #2: Tall (____) x Tall (_____) à First offspring (______)
Results:______à Second Offspring (______)
4. Mendel made some observations
Mendel determined that each organism must have 2 factors (one from ______and one from______) that determine the organism’s traits. These factors are known as ______, and each are located on the ______.
Each gene can exist in alternate forms, such as ______. These alternate or different forms are called ______.
Organisms usually have 2 alleles for each trait. One allele from the ______and the other allele from the ______.
5. Mendel’s Principles
a. Principle of Segregation (Separation): explains how ______for a trait but only donates ______to their offspring ______.
-Describes ______
b. Principle of Independent Assortment:
c. Principle of Dominance: There are ______alleles-one is______and the other called ______. Geneticists represent alleles by letters.
Dominant Trait:
Dominant Alleles Represented by ______:
Recessive Trait:
Recessive Alleles Represented by ______:
6. Representing Traits as Letters
Genotypes:
Examples of Genotypes:
7. Types of Genotypes
a. Homozygous:
Examples:
b. Heterozygous:
Examples:
8. Determining how an organism looks
Phenotype:
Examples of phenotypes:
Practice
1.
2. Genotypes in which the dominant trait is expressed: AA Dd EE ff Jj RR
3. Genotypes in which the recessive phenotype is expressed: aa Gg Ff KK rr
4. Examine the following Punnett squares and circle those that are correct.
5. What do the letters on the outside of the Punnett square stand for? ______
6. What do the letters on the inside of the Punnett square stand for? ______
7. In guinea pigs, short hair, H, is dominant to long hair, h. Complete the following Punnett squares according to the directions given. Then, fill in the blanks beside each Punnett square with the correct numbers.
a. One guinea pig is Hh and one is hh. P1 = ______x ______
b. Both guinea pigs are heterozygous for short hair. P1 = ______x ______
8. In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling.
Father’s phenotype ______Mother’s phenotype ______
Father’s genotype ______Mother’s genotype ______
What is the probability of this couple having a child who is a tongue roller? ______