ALL of Genetics Unit
Wednesday 2/11/2015
Genetics
Genetics – the study of how
organisms inherit different features
from their parents
• Parents send information about TRAITS
(characteristics ) to their offspring.
We refer to this information as a gene,
which is a segment of DNA that codes for a
specific trait.
• GENES are found on chromosomes and
are made up of DNA.
Each individual has two copies of a gene,
one from each Parent. (One copy from
_____ & One from _______)
•An ALLELE is a – form of a trait
A DOMINANT trait – the Powerful trait (the
stronger trait) always represented with a
Capital letter
Example:
A RECESSIVE trait – the weaker trait, can
be hidden by a dominant allele, always
represented with a lowercase letter
Example:
• If the ALLELES you got from each parent
are the same alleles the individual is said
to be Homozygous for the trait.
– Ex:
• Homologous chromosomes are
chromosomes with the ______
information, size, & shape. Homo means
the _________.
• If an individual has different alleles the
individual is said to be Heterozygous for
the trait.
• Ex. _______
• Hetero means the opposite of homo, it
means DIFFERENT
PHENOTYPE its ______________
appearance. What an organism _________
like. I remember “PH” Phenotype/Physical
Examples of Phenotypes:
Height
Or anything else you can SEE!
GENOTYPE – the types of ALLELES that
an organism has for a particular trait (i.e.
tongue rolling)
Examples of Genotypes:
,
,
(The combination of the two alleles you have
for a trait is your genotype)
GENOTYPE – the types of ALLELES that
an organism has for a particular trait (i.e.
tongue rolling)
Homozygous or Heterozygous refer to an
organism’s ____________________
(Phenotype or Genotype)
We defined the word “Hybrid” for our purposes it
means two different parents or traits. If you have
a ring that is a gold hybrid, it is made of some
different things besides gold. What word that we
discussed today would be a synonym (mean the
same thing) as the word “Hybrid”?
•Hybrid = ____________
If “Pure” means being the same throughout, as in
pure gold has only gold. What word we discussed
today would be a synonym (mean the same thing)
as the word “Purebred”?
Purebred = ________________________
QUESTIONS???
Genetics
Genetics – the study of how
organisms inherit different features
from their parents
New Tools
Punnett Square – diagram used to predict the
outcome of a genetic cross.
Created by Reginald Punnett (1875 –1967), a
British geneticist, in the early 1900s
Test Cross!
A test cross can be used to determine the
Genotype of an individual for which the only
the phenotype is known.
An individual with a dominant phenotype
could either have a _______________ or a
__________________ genotype.
Test Cross
An individual with a dominant phenotype
could either have a Homozygous (BB) or a
Heterozygous (Bb) genotype.
The ONLY way to efficiently test this is to
cross the individual of unknown genotype
with a ____________ _____________
individual, has the ____________
phenotype.
Question of the Day 1/29
In a test cross I would always breed an
individual with an unknown _________ but
Dominant __________ with an individual
who had a ________ _______ genotype and
therefore also a __________ phenotype
In peas Yellow is Dominant to green peas.
Intermediate Inheritance
Intermediate Inheritance/Incomplete Dominance
- is when two alleles BLEND together.
Co-Dominance = Dominant together
Co-Dominance means: BOTH alleles are
represented that is they both SHOW UP!
(They are dominant together)
Co-Dominance = Dominant together
Imagine crossing a black dog with a white dog and
getting puppies that were black and white spotted!
*This is not how Dalmatians are really made. 
Intermediate inheritance &
Co-Dominance
* The difference between Intermediate Inheritance &
Co-dominance is in the PHENOTYPE.
In Intermediate Inheritance (aka Incomplete
Dominance) the alleles _________ together.
In Codominance both alleles _____ _______, are
EXPERESSED (Both traits are seen in the phenotype)
Multiple alleles
Multiple alleles – Traits are controlled by more
than 2 possible alleles.
Each individual still only has 2 alleles – one from
Mom & one from Dad
Multiple alleles
There are four possible types of human blood:
– A, B, AB, and O
•These are expressed by immunoglobulin
proteins, so the three possible alleles are written
in this way:
IA & IB are both CO-DOMINANT (they both
_______ ___) and i is recessive to them.
Multiple alleles
Blood types in
Blood Type
Alleles
humans are a good
(________type) (_______type)
example of a
multiple allele trait.
AIA or IAi
I
- They are also an
example of
IBIB or IBi
CO-Dominance –
dominant together –
I A IB
Both alleles/traits
ii
_________ _____.
Mendel’s Law of Segregation

Each individual has a pair of factors (alleles) for
each trait

The alleles segregate (separate) during
gamete (sperm & egg) formation

Each gamete contains only one factor (allele) for
each trait

Fertilization gives the offspring two factors
(alleles) for each trait
Dihybrid Crosses
Up until now we have been looking at
Monohybrid crosses. Mono means _______.
This is to say that we have been looking at one
________, or characteristic, at a time. Often
times we want to look at two traits at once. If we
are looking at the outcomes of two traits in one
cross we will call it a __________ ___________.
•Di = _______
Mono = _________
Dihybrid Crosses
Often times we want to look at two traits at once.
If we are looking at the outcomes of two traits in
one cross we will call it a Dihybrid Cross
Di = _______
Mono = ______
Dihybrid Crosses
Dihybrid cross – two trait cross
In monohybrid crosses each parent was
represented with ___ alleles and there were ____
possible allele combinations.
(Ex. A parent could be AA, Aa, or aa)
Dihybrid Crosses
Dihybrid cross – two trait cross
In Dihybrid crosses there are ___ alleles/parent
(that is 2 alleles for each trait) and ____ possible
Allele Combinations.
Genetics & Probability
• Why might things not turn out the way we
expected them to????
•PROBABILITY – IT’S
JUST CHANCE!!
Polygenic Inheritance
–Many genes control a single trait
(2 or more genes)
• Traits tend to show CONTINUOUS
Variation (Not 2 discrete possibilities)
33
Genetics & Probability
What is “EPIgenetics”?
What are the 4 major factors that affect our
“EPIgenetics” (What genes are turned on/off)?
• Stress
• Toxins
• Diet/Nutrition
• Physical Activity
Genetics & Probability
Can we directly change our genetics (What we
inherited from our __________)?
Can we change our “Epigenetics” - what genes
are turned on/off? (Diet, Physical Activity, Exposure to Toxins, Stress)
Question of the Day 2/09
Give the sex chromosomes of a male & female.
Female:
Male:
Question of the Day 2/10
Give the genotypes of the following
individuals, looking at colorblindness, a
recessive X-linked (sex-linked) trait.
Color Blind Female:
Color Blind Male:
Carrier Female:
Non-color blind Male: