Chapter 11 lesson 1
Gregor Mendel= an Austrian monk who studied the genetics of Pea plants
 Self Pollination= 1 parent produces identical offspring (“True Breeding”)
 Cross Pollination= 2 Parents
Male sex cells in 1 plant fertilize the egg cells of another
*Mendel tried to stop self pollination from happening- he cut off the male parts
of a flower. Then he pollinated ONLY the plants he wanted.
Genes and Dominance
1. Traits= Specific characteristic that is different in organisms. (ExamplesPlant height or Plant color)
P= parent generation
F1= 1st generation of offspring
2. Hybrid= the offspring of parents with different traits
3. Alleles= different forms of a gene
1. Gene- height
2. Alleles- tall and short
4. Gene= chemical factor that determines traits
5. Segregation= separation of alleles
6. Gametes= Sex cells
1. Male- sperm
2. Female- egg
Dominant: Capital letter when present. Will always be seen.
Recessive: will remain hidden unless paired with another recessive gene
Examples for gene height
Tall= Dominant (T)
Short= recessive (t)
TT= Tall
Tt= Tall
tt= short
Chapter 11 Lesson 2
Probability is used to predict the outcome of a genetic cross
Punnet Square for Eye Color Cross
B= Brown (dominant)
b= blue (recessive)
Parents-Bb= brown
B
b
Bb
B BB
Brown Brown
bb
b Bb
Brown blue
Offspring
75% Brown
25% blue
Or 3:1
Homozygous= same alleles (example- TT or tt)
Heterozygous= different alleles (example- Tt AKA “Hybrid”)
Phenotype- Physical characteristics
 What it looks like (blue eyes)
Genotype- Genetic makeup

Example- bb
Chapter 11 Lesson3
Independent Assortment=traits do not influence the inheritance of other
traits
1. Mendel’s 2 factor cross (Round & Yellow) RY
and (Green and Wrinkled) ry
Incomplete Dominance= mix of 2 alleles
Example- Red Flowers (RR) and White Flowers (WW) gives you Pink
Flowers (RW)
Codominance= Both alleles are shown
Example- Black Chickens (BB) and White Chickens (WW) = Black AND
White Chickens (BW)
Multiple Alleles: Genes with more than 2 alleles.
Examples: rabbit coat color, Human eye color (brown, blue green),
human blood type
Polygenic Traits: Traits controlled by 2 or more genes. Different
combinations of alleles make different phenotypes.
Examples: Human skin color (this is the reason why we are all
different.)
Mendel’s Principles: (other scientists tested this)
 Also studied “Drosophila” (fruit Fly)
 Fruit Flies are useful in the study of genetics
 Easy to keep in a lab
 Produce a lot of offspring
 Reproduce quickly
Chapter 11 Lesson 4
Meiosis
Gametes: Sex cells (half the number of chromosomes)
o Sperm
o Egg
 Haploid:1 set N=4
o 1 copy of each gene
 Diploid: 2 sets 2N=8
o 2 copies of each gene
Homologous: Chromosomes come from both parents (Mom and Dad)matching chromosomes
Meiosis: Only occurs in Sex cells (gametes)
 The number of chromosomes per cell is cut in half
 Creates 4 genetically different haploid cells
Phases of Meiosis
1. Meiosis 1
i. Chromosomes form a tetrad (4 Chromosomes)
1. Crossing over=reason for differences in offspring.
Produces new combinations of alleles.
2. Meiosis 2
 Chromosomes divide again.
 This time there is NO replication of chromosomes
 ½ The Chromosome Number
 4 genetically different haploid cells
Chapter 11 lesson 5
Independent Assortment- genes are linked. Chromosomes assort separately
 Chromosomes are groups of linked genes.
 Gene Maps- chromosomes are NOT Linked Forever. Crossing over
prevents this. (Example- Asian eye shape and Brown hair)
 Distance between genes is mapped.
 Locations of each known human gene “Human Genome Project”