Download Gregor Mendels Experiments and Outcome dominnat and recessive

Data for Students from 2014/2015
Data for Students from 2014/2015
Data for Students from 2014/2015
Trait
348
349
Hand Clasping
Left on top 16
Right on top 14
13
17
14
15
Cleft Chin yes
Cleft Chin no
20
10
19
9
Hair on middle
finger
No hair on
middle finger
Right handed
Left handed
347
17
13
2016-2017 Results
Trait
347/348
Eye Color
Blue
Brown
Gray
Green
Hazel
Tongue Rolling Yes
Tongue Rolling No
PTC Yes
PTC No
Widow’s Peak
Straight Hairline
Attached Earlobe
Detached Earlobe
Cheek Dimples
No Cheek Dimples
347/348 LE
349/351 LE
Trait
Left Thumb on Top
Right Thumb on Top
Cleft Chin (Dimple)
Smooth Chin
Middle Finger Hair
No Middle Finger Hair
Right Handed
Left Handed
Normal Thumb
Hitchhiker Thumb
347/348
347/348 LE
349/351 LE
LT- Today, I can connect my observations of
human traits to Gregor Mendel’s studies by
comparing what I have found in my investigation
to his pea plant experiments.
Are there trends in the human traits data that we
are collecting?
Is there a relationship between our data and
Mendel’s data?
Human Chromosomes
46 chromosomes
23 pairs
Remember:
Chromosomes come in pairs.
Chromosome pair 2
Mom
Dad
Eye Color
The genes along the
chromosomes code for the
same gene, but can be a
different variation of the
trait.
For all traits, you have two genes (one came from mom
and the other from dad)
Allele- one of two alternate or similar forms of a gene.
Ex) In your DNA, you may have an allele for
brown hair and an allele for blond hair.
Or you may have 2 alleles for blond hair.
Or 2 alleles for brown hair.
When genes pair up, there are different relationships that
they could have with each other:
Labrador Retrievers
Huskies
Labrador and a Husky
Purebred= has no variation for a trait.
For example, a plant that can only produce
offspring with purple flowers.
Or a plant that can only produce offspring
with white flowers.
Hybrid= has variation for a trait.
For example, a plant that can produce
offspring with purple and white flowers.
Are these alleles examples of purebred or
hybrid?
1. EE
2. ee
3. Ee
4. Dd
6. DD
7. dd
Gregor Mendel
Mendel's pea plant experiments conducted between
1856 and 1863 established many of the rules
of heredity, now referred to as the laws of Mendelian
inheritance.
Mendel noticed:
Some traits show up more frequently than others.
Some traits seemed to be passed from parents to
offspring , while others did not seem to be (meaning the
parents did not appear to have the trait).
Pea Plant Experiments
Trying to get answers as to why these
trends occurred amongst traits, Gregor decided
to experiment with pea plants.
Why pea plants, you ask?
When pea plants are bred, the offspring
grow into adulthood quickly.
Therefore, he could observe the traits of
many generations of pea plants.
Let’s look at
what he did!!!!!
Homework:
Define in your notebook:
Genotype
Phenotype
Dominant Allele
Recessive Allele
Homozygous Dominant
Homozygous Recessive
Heterozygous
Introduction to Mendelian Genetics Lab” questions
1- Extension 1.
Mendel bred a purebred purple flower with
a purebred white flower.
Let’s give his flowers letters for the alleles.
Let’s use P for purple and W for white.
What do you think the flower color of the
offspring were? What percent were
purple versus white? Why?
What do you think the alleles are for these
offspring?
Mendel then bred hybrids (PW) flowers.
What do you think the flower color of the
offspring were? What percent were
purple versus white? Why?
Recreate the experiment on the “Gregor Mendel’s
Pea Plant Flower Experiment” sheet.
Including the 2 questions that you have about the
outcome of his experiments.
Print it. One for each partner.
Color in the flowers.
Give in to me.
I will review it and make comments.
You fix mistakes.
One of Mendel’s Experiments:
He bred a purebred purple
flower with a pure purebred
white flower.
The offspring only had purple
flowers.
Unusual?????????
These offspring are
hybrids because they have one parent with
purple flowers and the other with white.
He then bred two hybrids.
In the second generation (the
offspring of the hybrids), there
was a mix of purple and white
flowers.
But, on average, there were more purple
than white when two hybrids were bred.
The ratio was 75% purple to 25% white.
Why do we notice trends that occur in Mendel’s
experiments and in our inventory of traits?
What are the trends that we noticed in our data?
Some variations of a trait show up more
frequently.
For Example, brown eyes show up more frequently
than blue eyes.
What are the trends that Mendel noticed in his
data?
Some variations of a trait show up more
frequently.
For example, purple flowers show up more
frequently than white in pea plants.
Now we have to find out why!!!!
What questions do you have?
Why do some variations of a trait show up more frequently than
others?
Why do some traits show in the offspring but not the parents?
Why does the F1 generation have only one variation of the trait?
Why is there a 75% 25% ratio in the F2 generation?
What do you think Mendel’s experiments proved or showed?
Mendel’s studies gave some answers to the above questions.
Is there a relationship between Mendel’s data and your data?
The relationship between Mendel’s data and my data is that in his
pea plant studies there are variations of a trait that are more common which
is what we discovered in the inventory of our classmates traits.
The traits such as the flower color of Mendel’s pea plants are known
as:
Inherited traits- Traits that are passed from parent to offspring.
Exactly how do parents pass on traits to their offspring?
Gene- an inherited bit of information that is passed directly from
parents cells to offspring cells.
Genes are found along a DNA strand (i.e.- a DNA strand is
made up of a sequence of genes that are codes for different traits)
What if a trait is not passed from parent to offspring?
How does one get a trait that is not inherited?
Non-inherited Trait- learned traits or physical traits that we acquire
from the environment.
Genotype- the genetic makeup of an organism
(What is found on the DNA). We use capital and
lowercase letters to express genotype.
The genotype of blue eyes may look like this:
ATGCTAG
TACGATC
Phenotype- what an organism looks like as a result
of its genotype (physically or behaviorally shows).
We use character descriptions to express
phenotype.
Blue eyes physically
showing is the
phenotype
Mendelian Genetics
Sometimes genes can be dominant and recessive.
Dominant Gene (allele)- A variation of a trait that is stronger and masks a weaker trait.
Capital letters are used to represent dominant genes.
We use capital letters to represent a dominant trait.
Example: Brown Eyes= E
If this trait is present in an individuals DNA, it will show up as a physical characteristic
of that individual.
Recessive Gene (allele)- A variation of a trait that is weaker and is masked by a
stronger trait. Lower case letters are used to represent recessive genes.
We use lower case letters to represent recessive traits.
Example: Blue Eyes= e
If this trait is present in an individuals DNA, it will not always show up as a physical
characteristic. It will only show if the person’s alleles are both this trait.
Homozygous- two of the same alleles for a gene.
TT or tt
Homozygous dominantTT alleles are identical and
dominant.
Homozygous recessivett alleles are identical and recessive.
Heterozygous- two different alleles for a gene.
Tt alleles are different.
Mendel’s experiments were done mostly on pea
plants.
Understanding why pea plants have purple vs.
white flowers doesn’t seem important to the
average person,
DOES IT?
Why should we care about Mendel’s studies?
The next video is one of many examples of why
Mendel’s studies are important to all of us, not just
those who study or practice science.
Genetic Disease/DisorderAn inherited disease or disorder that caused by
a mutation in a gene or by a chromosomal
defect.
LT- Today, I can apply my understanding of the
relationship between allele pairs by comparing
and contrasting dominant and recessive,
codominant, and incomplete dominant alleles as
I create my own critter pup.
What is the phenotype outcome when both the
dominant and recessive alleles are in an
individual’ s genotype?
Mendelian Genetics
Dominant and Recessive Alleles
Example
Trait= Human Hair Color Brown Hair (B)
Blonde Hair (b)
Genotype
Phenotype
BB
Brown
bb
Blonde
Bb
Brown
When sex cells (sperm and egg) are being made, it
is like the toss of a coin for which allele will go into
the sex cell.
It’s a 50/50 chance.
But remember, a parent can only give a variation of
an allele that they have in their genotypeYOU CAN’T GIVE SOMETHING YOU DO NOT HAVE
TO GIVE!!!
What are non-Mendelian traits?
What are codominant traits?
What are incomplete dominant traits?
Non-Mendelian Genetics
When different alleles that we inherit from our
parents come together they can have different
relationships:
Codominant Alleles
Example
Trait= Certain Horse breeds fur color
Black (B)
White (W)
Genotype
Phenotype
BB
Black
WW
White
BW
Black and White Spots
Incomplete Dominant Alleles
Example
Trait= Certain Rabbit breeds fur color Black (B)
White (W)
Genotype
Phenotype
BB
Black
WW
White
BW
Grey
Dominant and Recessive Alleles
One allele is dominant over the other. When they are in an
individual’s genotype together the dominant allele shows in the
phenotype.
Codominant Alleles
The 2 alleles are equally dominant. When they are in an
individual’s genotype together they both show in the phenotype
but separately. This could be in the form of spots, stripes, etc.
We use two different capitalized letters to represent the alleles.
Incomplete Dominant Alleles
The 2 alleles are equally dominant. When they are in an
individual’s genotype together they both show in the phenotype,
but they make a third trait by blending.
We use two different capitalized letters to represent the alleles.