Warm Up
 Tuesday,
January 8, 2013
1. List the thing you enjoyed the most
over your holiday break?
2. State one fact you know about
genetics/DNA.
Genetics #1:
Introduction to Genetics & Gregor Mendel
Reminder:
Cornell Notes

Divide your paper
◦ Cues Section (1/3 page)
◦ Notes Section (2/3 page)

At the END of today:
◦ Draw a horizontal line at end of notes
◦ 3-5 complete sentence summary of that day’s
notes
◦ Must include SPECIFICS
Objectives
Describe the importance of Gregor
Mendel.
2. Define the term traits.
1.
Genetics
= study of heredity


All living thing (plant,
animal, or microbe)
has a set of
characteristics/traits
Inherit from parent(s)
Review: Meiosis

Fertilization
◦ Sexual reproduction
◦ Male sperm & female egg join
 Each haploid
 Latin Root: hapl = single
◦ Produce new cell
 Diploid
 Latin Root: diplo = double
◦ Develops into embryo (seeds in plants)
Gregor Mendel:
Austrian monk, teacher,
scientist, botanist
 Studied peas in 19th
century (1800’s)

 Made observations
 Designed experiments
 Mathematical analysis

Known as Father of
Genetics
Gregor Mendel’s Work

Bred peas in garden
1) Cross pollinated true
breeding parent plants
2) Raised plants from
seeds & made
observations
3) Allowed offspring to
self-bred & observed
their offspring
True-breeding
AKA pure-bred
 SAME characteristics
seen in parent &
offspring
(IDENTICAL)
 Do NOT see any
other characteristics

The Original Plants


Plants in 1 section had
different characteristics
than plants in another
section
Example:




Seeds
Seeds
Plants
Plants
#1
#2
#1
#2
Tall plants
Short plants
green seeds
yellow seeds
Traits
= specific characteristics (examples: seed/flower
color, eye color, hair color)
 Mendel studied 7 different pea plant traits
Worksheet:
Karyotyping
Karyotype = picture of
chromosomes
 Used to detect chromosomal
abnormalities

***Latin Root: karyo = nucleus***
Warm Up
 Wednesday,
 Who
January 9, 2013
is the Father of Genetics?
Genetics #2:
Mendel’s Genetic Crosses, Dominance, Segregation
Objectives
Contrast dominant and recessive alleles
2. Define the term allele.
1.
P generation
Original generation
of plants
 Parents called P or
“parental”
generation

◦ Bridget & Brendan
are the parents
therefore they are
the P generation
P
P
F1 generation

Offspring called F1
or “first filial”
generation
◦ Filius and filia are the
Latin words for “son”
and “daughter”
◦ Kaya & Dorian are the
children therefore
they are the F1
generation
F1
F1
Hybrids
= combination of 2 different things
= offspring of crosses between parents w/
different traits
 Ex:
◦ Zonkey
(donkey & zebra)
◦ Liger
(tiger & lion)
◦ Toyota Prius
(electric & gas)
Mendel’s Cross
Pollination Experiments
Cross Pollination = breeding 2 plants
that have different characteristics
 What did he do?

◦ Crossed parent plants w/ different
characteristics (tall, short, green seeds, yellow
seeds)
◦ Studied the offspring
What were the results?
Mixture of all the traits?
NO, all hybrids had characteristics of only
ONE parents
 In each cross, the character of the other
parent seemed to disappear!

Dominance
= Have 2 different traits in parents, but
only see 1 trait in offspring
 Dominant Trait = Trait you see
 Recessive Trait = Trait you do NOT see
Parent:
Blue
Eyes
Parent:
Brown
Eyes
Child:
Brown
Eyes
Phenotype vs Genotype

Phenotype = physical characteristics
◦ Example: brown or blue eyes

Genotype = genetic characteristics
◦ Example: BB, Bb, or bb
1st Conclusion:
Genes = biological inheritance is
determined by factors that are passed
from one generation to the next (parent
to offspring)
 Alleles = different forms of a gene

◦ One on every chromosome
2nd conclusion:
Principle of Dominance


States some alleles are dominant & others are
recessive
An organism with a dominant allele will
ALWAYS show the dominant trait
Mendel’s Findings

Result:
All seeds yellow
◦ Yellow seeds = Dominant
◦ Green seeds = recessive
What happened to the
recessive traits?
Did they disappear? Did they segregate?
 Experiment #2:

◦ Crossed the different F1 generation
◦ Made F2 generation
Mendel’s 2nd Experiment

Results:
◦ Recessive traits
reappeared
◦ ¼ or 25% of the
plants had
recessive traits
in F2 generation
Conclusion: Mendel’s
Law of Segregation

F1 plants produced gametes (sex cells)
◦ 2 alleles segregated from one another
◦ each gamete carried a single copy of the gene
In the F1 generation, each gamete had 1
copy of the green gene or one copy of
the yellow gene.
 AKA Principle of Independent Assortment

Common Human
Dominant Traits
Thinking Strategy
#19 T-Shirt Design
• Directions: Design artwork for a t-shirt
representing Mendel’s Genetics
1) Front of shirt must have artwork showing the
concept using 3 colors
2) Back of the shirt must have a 1-2 line cute or
clever (but clean) saying.
3) A minimum of one paragraph (4-5 sentences)
must be written to describe how the artwork
and saying explain Mendel’s Genetics.
Warm Up
 Thursday,
January 10, 2013
What is the difference between a
dominant trait and a recessive trait?
Genetics #3:
Probability, Punnett Squares,
Monohybrid Crosses
Objectives
Define the term punnett square.
2. Predict the outcome of genetic crosses
using punnett squares.
1.
Genetics & Probability:

Probability = likelihood that an event will
occur

Example: Coin toss
◦ 2 possibilities: head or tails
◦ probability of heads is 1 in 2 chance
◦ i.e. ½ or 50% chance
Genetics & Probability:

Example Problem: If you flip a coin 3
times in a row what are the chances that
you will get heads every time?

Answer:
◦
◦
◦
◦
Toss #1 have a 1 in 2 chance
Same for Tosses #2 & #3
½ x ½ x ½ = 1/8
1 in 8 chance of flipping heads 3 times in a
row!
Genetics & Probability:
 Principles
of probability are
used to predict the outcomes
of genetic crosses
Punnett Squares
= Diagram that shows the gene
combinations that might result from a
genetic cross
Homozygous vs
Heterozygous

Homozygous = 2 identical alleles (TT or
tt)
◦ Considered true-breeding
◦ Latin Roots: Hom = same

Heterozygous = 2 different alleles (Tt)
◦ Considered Hybrids
◦ Latin Roots: Hetero = other, different
Set up a Punnett square
(Monohybrid Square)

1. Set up a 2 by 2
Punnett square
(monohybrid cross)
Set up a Punnett square
2. Write the alleles for
parent 1 on left side of
Punnett square
 Each gamete will have 1
of the 2 parental alleles
 1/2 of the gametes will
have the dominant (T)
allele
 1/2 will have the
recessive (t) allele
Set up a Punnett square
3. Write the allele for
parent 2 above the
Punnett square
 This parent is
heterozygous(Tt)
 ½ the gametes will have
the dominant (T) allele
 1/2 will have the
recessive (t) allele
Fill in a Punnett square
4. Fill in the squares
for parent 1.
 Fill each square with
the allele from
Parent 1 that lines
up with the row.
T
T
t
t
Fill in a Punnett square
5. Fill in the square for
parent 2.
 Fill each square with
the allele from
Parent 2 that lines
up with the column.
TT
Tt
Tt
tt
Genotypes that resulted from
monohybrid cross (Tt x Tt)

TT
Tt
tt
Tt
25%
50%
25%
homozygous
heterozygous
homozygous
dominant
dominant
recessive
Phenotypes that resulted from
monohybrid cross (Tt x Tt)

75% Tall
◦ TT = homozygous dominant
◦ Tt = heterozygous dominant

25% Short
◦ tt = homozygous recessive
Warm Up
 Friday,
1.
2.
January 11, 2013
What is the difference between
genotype and phenotype?
Using the letter “A,” give an
example of a genotype that is
homozygous dominant?
Warm Up
Monday, January 14, 2013
1.
List the genotypes and their
percentages for the punnett square
above.
Human Genome Video
Warm Up
 Tuesday,
January 15, 2013
Complete the following monohybrid
punnett square:
Genetics #4:
Punnett Squares & Dihybrid
Crosses
Objectives
Define the term dihybrid cross.
2. Predict the outcome of independent
assortment using a dihybrid cross.
1.
Dihybrid Crosses
= 2 factor cross for 2
different traits
 Example:
◦ Bb
 B = Brown Eyes
 b = Blue Eyes
◦ Ss
 S = Tall
 s = Short
Heterozygous
Dihybrid Crosses
9:3:3:1 results anytime you have 2
heterozygous adults
 Example

◦
◦
◦
◦
9 brown eye & tall
3 brown eye & short
3 blue eye & Tall
1 blue eye & short
(recessive both traits)
Warm Up
 Wednesday,
January 16, 2013
What is the ratio that results from
crossing two heterozygous parents in
a dihybrid cross?
Latin Roots Quiz
 Take
everything off your desk except
something to write with.
Warm Up
 Thursday,
1.
January 17, 2013
Write out the gametes for a guinea
pig with the genotype AaBb.
AaBb
Genetics #5:
Co-Dominance & Incomplete
Dominance
Objectives
Define incomplete dominance.
2. Predict the outcomes of incomplete and
codominance.
1.
Summary of
Mendel’s Principles:

Inheritance of biological characteristics
◦ Determined by genes
◦ Passed from parents to offspring

Adults have 2 copies of each gene
◦ 1 from each parent

Genes usually segregate independently
Beyond Dominance

Some alleles are
neither dominant nor
recessive.
◦ Example: height
Many traits controlled
by multiple alleles or
genes
 Mendel did not
understand this
complex relationships

Incomplete Dominance
= blending of parental traits
 Example:
◦ F1: red flower (RR) and white flower (rr)
◦ F2: pink (Rr)
Codominance:
= see both alleles in phenotype
 Heterozygous
 Neither dominant or recessive phenotype
 Hybrid trait
 Example: Roan Coat in Horses
◦ Red + White = Red & White Coat
Codominance: Blood Types

Blood Type A
◦ Option 1: IAIA
◦ Option 2: IAi

Blood Type B
◦ Option 1: IBIB
◦ Option 2: IBi

Blood Type AB
◦ Only Option: IAIB

Blood Type O
◦ Only Option: ii
Codominance: Blood Types

Which blood types are Co-Dominant?
◦ Blood Types A & B (IAIB)

Which blood type is recessive?
◦ Blood Type O (ii)
Pedigrees
= diagram that
shows occurrence of
particular genes
within a family
 Shows inherited
traits
 Shapes:
◦ Circle = Female
◦ Square = Male
Multiple Alleles
= 3 or more alleles code for a trait
 Example:
◦ Blood Types:
 IA
 IB
i
◦ coat color of rabbits
Polygenic traits
= interactions of several
genes at different loci
 Ex: height, skin color,
weight
Remember:
 Locus = location on
chromosome
Warm Up
 Friday,
January 18, 2013
What are the four possible blood
types for humans?
Genetics Quiz
Get out something to write with and keep
your genetics notes out on your desk.
Warm Up
 Tuesday,
January 22, 2013
What would be the 4 female gametes
from the following genotype: AABb?
Blood Typing
&
Pedigrees
Warm Up
 Wednesday,
January 23, 2013
What is a pedigree? Define in words
AND with a picture.
Genetics Review
Stations
Warm Up
 Thursday,
January 24, 2013
What is the difference between
incomplete dominance and
codominance?
Gems of Wisdom:
Genetics
Warm Up
 Friday,
January 25, 2013
Using the letters “B” and “R” (dihybrid
cross), write a homozygous
dominant genotype.