Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Focus 10-1: Genetics

No description
by

Nicole Martin

on 17 November 2017

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Focus 10-1: Genetics

Genetics
Focus 10
BOCW
Brainstorm: What is the purpose of DNA?
write a least TWO things!
Essential Question
What is the difference between a genotype and a phenotype?
Think - Pair - Share
What are some
physical traits
that you and your parents have in common?

What are some
diseases
that you and your extended family have in common?

Thinking Deeper
Do you own a purebred dog or cat?

What makes them purebred?
How do you know they are purebred?

Gregor Johann
Mendel
Responsible for the Laws of Inheritance

1822-1884
Father of genetics
He was a friar (kind of like a monk).
More about... MENDEL
Studied the inheritance of traits in pea plants

Mendel's work was not recognized until the turn of the 20th century

Mendel cultivated and tested some 28,000 pea plants

He found that the plants' offspring retained traits of the parents

Mendel focused on...
Plant height
Pod shape and color
Seed shape and color
Flower position and color
Site of Gregor Mendel’s Experimental Garden
Czech Republic
Mendel's Idea
Particulate Inheritance
Mendel stated that physical traits are inherited as “particles”

Did not know that the “particles” were actually Chromosomes & DNA

Genetic Terminology
Heredity / Inheritance
- passing of traits from parent to offspring

Trait
- any characteristic that can be passed from parent to offspring
Genetics
- study of heredity

Gene Terminology
Alleles
- two forms of a gene (dominant & recessive)

Dominant
- stronger of two genes expressed; represented by a capital letter
(R)

Recessive
- gene that shows up less often; represented by a lowercase letter
(r)

A couple more terms...
Genotype
- gene combination for a trait
(e.g. RR, rr) -
Letters

Phenotype
- the physical feature resulting from a genotype (e.g. red, white) -
Words

Describe the genotype for the boy's hair.
Describe the phenotype for the boy's hair.
Flower Example
Genotype of alleles:
R
= red flower
r
= yellow flower
All genes occur in pairs, so
2 alleles
affect a characteristic

Possible combinations are:

Genotypes:
RR R
r rr

Phenotypes:
RED RED

YELLOW
Genotype vs. Phenotype
The girl has blonde hair.
The girl's hair is bb.
The girl has blue eyes.
The girl's eyes are tt.
Generations
P1 Generation
= the parents

F1 generation
= the first-generation offspring

F2 generation
= the second-generation offspring

What about this example?
Label Generations
P1
F1
F2
Genetic Crosses
1. Monohybrid: Examines ONE trait.
2. Dihybrid: Examines TWO traits.
Phenotype?
Genotype?
Phenotype?

Genotype?
Monohybrid Crosses
Genetic Crosses
Show possible outcomes of genes that the new generation will have.

We will use...
Punnett Squares
Gene Diagrams
Monohybrid Crosses
Mating between two individuals
Focuses on two alleles for only one trait
Examples...
Cross between short plant and tall plant.
Cross between a blonde woman and a man with brown hair.
Punnett Square
A grid for organizing genetic information.

Named after Reginald C. Punnett, who devised the approach.
Shows
probabilities
, not actual results.

Steps to Complete a Punnett Square
1. Make a
key

2. Determine parent’s
genotype

3.
“Split” the letters
of the genotype for each parent and put them “outside” the P-Square

4. Determine the genotypes of the offspring by
filling in the P-Square

5.
Summarize
results

Step 1 – Make a Key
IMPORTANT -> do this EVERY time!

Always include:
Trait
Dominant Allele
Recessive Allele

Trait: Eye color
Dominant: Brown (B)
Recessive: blue (b)
Without this I will mark it WRONG!
Step 2: Parent’s Genotypes
Sometimes the parents genotype is given in the genetic problem

Other times you will have to use your understanding of the vocab
to determine the genotypes

Example: Cross a short pea plant with one that is heterozygous for tallness. Short is recessive.
Possible Genotypes
Homozygous
:
Both alleles are the same.
ie: BB or bb
Heterozygous
:
Alleles are different.
ie: Bb
Homozygous dominant
: BB - 2 dominant alleles
Homozygous recessive
: bb - 2 recessive alleles
Remember... the DOMINANT allele is ALWAYS expressed!!!
*Brown eyes (B) is dominant to blue eyes(b).
Genotype Phenotype
BB
Brown eyes
bb
Blue eyes
Bb
Brown eyes
tt x Tt
Step 3: "Split" the Parents
Parents:
First parent: left side

t
t
T
t
Second parent:top
Step 4: Fill in the P-Square
t
t
T
t
1. top left
2. bottom left
3. top right
4. bottom right
*write dominant alleles 1st!
T
t
T
t
t
t
t
t
Step 5: Summarize Results
Genotypes:
50% heterozygous
50% homozygous recessive
Phenotypes:
50% Tall
50% Short
Practice Problem #1 - Left Side
Practice Together
In silkworms, a yellow cocoon is
dominant
to a white cocoon. Figure out the genotype and phenotypes of the offspring if a heterozygous yellow is crossed with a heterozygous yellow.

Practice Problem #2 - Left Side
Independent Practice
In pea plants, spherical seeds (S) are
dominant
to dented seeds (s). In a genetic cross of
homozygous dominant
and
homozygous recessive
for the seed shape trait, what would the genotypes and phenotypes of the offspring be?
Independent Practice
Remember to do
ALL
steps neatly!
ASK
if you need help!
TURN IN
when you are done!
Exit Ticket
Green feathers are dominant to blue feathers. In a cross between a heterozygous bird and a blue bird, what percentage of the offspring would be blue?
Dihybrid Crosses
honors only
BOCW
If a homozygous dominant individual mates with a homozygous individual the genotypic and phenotypic percentage is ALWAYS...
Essential Question
How can I use a dihybrid cross to determine TWO traits in offspring?
Dihybrid Cross
A cross between two individuals that differ in
two traits
 of particular interest.

Both parents will be heterozygous or homozygous (dominant/recessive) for
two traits at the same time
.

Two monohybrid
crosses put together


Let's practice TOGETHER
Norway Rats are usually brown (B), but a few are white (b). They usually have long tails (T), but some have short tails (t).
A rat that is homozygous dominant for both traits mates with a white rat with a short tail.
Think about all combos
Parent 1: BBTT
You need to "FOIL"!!!
F
- BT
O
-BT
I
- BT
L
- BT
Parent 2: bbtt
F
-bt
O
- bt
I
- bt
L
- bt
F - First
L - Last
I - Inner
O - Outer
BT
BT
BT
BT
bt
bt
bt
bt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
BbTt
Final Results:
Genotype - 100% heterozygous color
100% heterozygous tail
Phenotype - 100% brown, long tail
Let's make it harder...
Two rats are heterozygous for both color and tail length.
What will their offspring's genotype and phenotype be?
Both parents:
BbTt
F- BT
O- Bt
I- bT
L- bt
BT
BT
Bt
Bt
bT
bT
bt
bt
BBTT
BBTt
BbTT
BbTt
BBTt
BBtt
BbTt
Bbtt
BbTT
BbTt
bbTT
bbTt
BbTt
Bbtt
bbTt
bbtt
9
:
3
:
3
:
1
phenotypic ratio!!!
Group Practice
Wall problems & carousel walk.
1. Tape your problem to the butcher paper.
2. As a team, solve the problem.
3. Hang it up and go back to your seat.
Exit Ticket
What does F.O.I.L. stand for?
What is its purpose?
Inheritance Patterns
BOCW
If red is dominant to yellow in flowers, what will the phenotype of a heterozygous flower be?

WHY?
Essential Question
How do incomplete and co-dominance differ from previous mono-hybrid crosses?
Mendel didn't think of this!
Incomplete Dominance
A cross between organisms with two different phenotypes produces offspring with a third phenotype that is a 
blending
 of the parental traits.

RED
 Flower X  
WHITE
 Flower ---> 
PINK
 Flower


Left Side - Incomplete #1
A female black hair mouse is crossed with a male white hair mouse.

What could the offspring look like

State the genotype of the parents

State the phenotype of the parents
Left Side - Incomplete #2
A red daisy and yellow daisy cross.
What would the offspring look like?
Would they all be the same?
Co-Dominance
Complete Dominance
Everything we have learned so far.
The dominant allele
completely
blocks out the recessive allele in heterozygous individuals.
Bb = brown eyes
Only homozygous recessive bb can cause a recessive phenotype.
Two different phenotypes produces offspring with a third phenotype in which
both
of the parental traits appear 
together


blue
 x 
red
 ---> 
b
l
u
e
 
&
 
r
e
d
 
s
p
o
t
t
e
d

Left Side - Codominance #1
A brown cow mates with a white cow. What does the offspring look like?
Brown and white spotted!
Practice
Problems
Exit Ticket
States the difference between incomplete and co-dominance.
Use capital and lower case of same letter!
Use different capital letters!
2 types
Full transcript