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Intro To
Genetics
Vocab & Skills
Gregor Mendel
“The Father of Modern Genetics”
Crossed pea plants that varied in 7
different contrasting traits:
• height
•seed color
•seed texture (round vs. wrinkled)
• and others…
Gregor Mendel’s Experiment
P 1 Generation =
Parents
_________________________________
F 1 Generation =
Children
_________________________________
Purebred
Purebred
Tall
Short
All Tall
F 1 Generation =
Children
_________________________________
All Tall
F 2 Generation =
3 Tall
Grand Children
_________________________________
1 Short
Discovering
Genes
Purebred
Purebred
Tall
Short
First Mendel thought T T
that the flowers must
That
Didn’t
Workor
So then
have
one gene
Mendel
that
factor thought
for height:
Maybe there are 2 genes
& one from each
for height
parent
That only one parent
could&pass it on toT t
their offspringOne was “stronger” than
the other
tt
All Tall
Tt
Tt
Tt
3 Tall
1 Short
TT
Tt
Tt
Tt t
P1
Tall
Short
TT
tt
T
T
F1
Tt
T
F2
t
TT
Genes
Separate
One Gets
passed on
from
parents
t
Tt
t
Tt
T
Tt
Genes are sorted
independently
from each other
t
tt
Mendel’s Contribution to Genetics (What he discovered)
1) 2 Genes for every trait - (1 from each parent)
2) One gene can be stronger &“take over”(Tt = Tall )
-Called ( Law of Dominance)
3) Traits can skip a generation (short)
Why did he study Pea Plants
- Reproduce Quickly
- Easy to see the traits
Genetics Intro
Vocab
Gregor Mendel -
Father of Genetics
“_____________________”Austrian
Monk
Pea
who tested ______Plants
for heredity
Heredity - The passing on of features or characteristics fromParents
________ to Children
_______
Traits – __________________________________________
Inherited Characteristics
Examples of Inherited traits:
Eye Color
Height
Intelligence
___________
____________
______________
Vocab Cont..
Genetics - The Study of __________________.
Heredity
2 genes
 Each Organism has ______________
for each trait, called ALLELES.
o
One from their mother and one from their father.
b
B
bb
BB
Don’t write: Each
parent can only pass
on 1 of their 2 Genes
to child
Bb
Child
Don’t write:
Child is a combo
( half mom & half dad)
Genetics Vocab
Cont..
Hints
Type or Form of a gene (one gene) 1 Letter
Alleles - ________________________________________
Allele = Alone
Example: T = tall gene t = short gene
makeup (2 gene combo)
Genotype – Genetic
____________________________________
Example:
(2 genes)
TT or Tt or tt
Physical appearance (what you see)
Phenotype - _________________________________
Example:
2 Letters
Tall or Short
Words
Pheno =Physical
Dominant vs Recessive
Dominant
Recessive
Who do you think would DOMINATE ?
Recessive = Hidden
“not actually seen”
Reminds me
of
Receding “going away”
Okay
back to
notes
Dominant vs Recessive
Dominant Genes – “____________________”
always takes over.
Stronger gene
Uppercase letter
- Allele is always abbreviated with an_______________
( B =– ____________eyes
– Dominant Allele)
Brown
Recessive Genes – “_____________________”
seems to disappear.
Hidden (weaker) gene
Allele is always abbreviated with a_______________
Lowercase letter
( b =– ____________eyes
– Recessive Allele)
blue
Lets Look at : Dominant / Recessive
Tongue Rolling
Traits in Humans
Can = Dominant : TT or Tt
Can’t = Recessive : tt
Earlobes
Attached = Dominant : EE or Ee
Unattached = Recessive : ee
Lets Look at : Dominant / Recessive
Traits in Humans
Thumb
Hitch Hiker = Dominant
Straight = Recessive
Lets Look at : Dominant / Recessive
Traits in Humans
Homozygous & Heterozygous
Homozygous: When two alleles Are
____________________
the SAME size letters.
same
( ____
BB or _____
bb = Homozygous Genotypes)
Heterozygous– When two alleles Are
____________________
DIFFERENT size letters.
different
( ______
Bb = Heterozygous Genotypes)
Back to Genes
HOW THEY ARE WRITTEN
When writing out genotypes & alleles remember to:
T = tall
t = short
1) Use the same letter for dominant & recessive genes: _____________
Tt not tT
2) If Heterozygous: The dominant (Capitol ) letter comes first.Bb
___________
not bB
2 - BB or bb
How Many Choices are there for Homozygous? ________
1 - Bb
How many choices are there for Heterozygous? _______
How they Work
Blue/Brown Eye color
Remember:
Alleles: (cheat sheet)
B - Brown
Dominant Allele - _______
b - blue
Recessive Allele - ________
3 Genotypes :
Capitol is Dominant
over Recessive
BB = Dominant shows = ____________________
Brown eyes
_______
( Phenotype)
T t = Tall
Bb = Dominant shows “takes over” = __________________
Brown eyes (Phenotype)
_______
Capitol
* Anytime you see a ___________________
( Dominant Allele)
So it shows:
Recessive is still
theretrait)
& can
be
- That __________________
(physical
will show.
Dominant
passed on to kids but… We don’t SEE it..
bb
blue eyes
_______
= Recessive shows - ________________
(Phenotype)
Lowercase together will the
* Only when there are TWO ________________
Recessive
_________________
(physical trait show)
Practice Vocab“ Look back at notes If need to”
Label the following as : GENOTYPE / PHENOTYPE / or ALLELE
Genotype
t = _________
Tt = _____________
Allele
phenotype
Dark hair = _____________
Label the following as : HETEROZYGOUS / or HOMOZYGOUS
ANSWERS
Homozygous
TT = ______________
Heterozygous
Homozygous
tt = _________________
Tt = ______________
Label the following with the correct Phenotype if : F = Freckles f = No Freckles
Freckles
Ff = _____________
(Freckles / No Freckles)
No Freckles
ff = _______________
(Freckles / No Freckles)
Freckles
FF = _____________
(Freckles / No Freckles)
Complete On Own:
“Gene Practice Problems”
Page in Packet
Warm Up
• Define the following words:
– Dominant
– Recessive
– Homozygous
– Heterozygous
Take out note packet and open up to last nights homework
Parents
Punnett Square Notes
Child Child
Child Child
Definition:Tool used to ___________the
possible _______
Child outcomes.
Predict
Outside
Inside
(Parents - ___________
/ Children - _________)
Example: Pea Color:
Allele:
G = Green
g = Yellow
Parent 1 = Gg: ___________
X Parent 2 = Gg: __________
Green
Green
Parent 1 = Gg: _____________X
Parent 2 = Gg: ________
Green
Green
G
Parents
G
g
GG
g
Gg
Green
Green
( ___________
) ( ___________
)
Gg
gg
Green
( ___________
) ( ___________
)
Yellow
All Possible Children
Punnett Cont..
G
g
G
g
GG
Gg
Green
Green
Gg
gg
Green
Yellow
Chances: %
25%
25%
Genotype Ratio:
25%
25%
1) Write 3 genotypes
1 GG :
_____
Phenotype Ratio:
75
% Green Children = ________%
% Yellow Children = _______%
25
2) Count Boxes
1 gg
: _____
2
Gg
_____
1) Write 2 Phenotypes
3 Green :
_____
2) Count Boxes
1 Yellow
_____
Punnett Practice
1. R = Red Flower
r = White Flower
Cross : Red and White Flower = R r X
R
r
r
Rr
Red )
( _______
rr
( _______
White )
r
Rr
rr
Red ) ( ________
White )
( ________
rr
a. What percent (%) of the
children will be:
50 %
Red _______
White _______
50 %
b. Genotype Ratio:
0
2
2
_____RR
: ____Rr
: ____rr
c.
Phenotype Ratio:
2
2
____Red
: ____White
Punnett Practice
Rr
Rr
1. Cross 2 Heterozygous Red Parents _______ X _________
a.
R
R
r
What are the chances of
getting a white flower?
25 %
White Flower _______
b. What are the chances of
getting a Red flower?
75
Red Flower _______
%
DO
one
RR the Last
Rr
Redyour
(on
_______
) ( _______
)
Red
own
1
b. Genotype Ratio:
2
1
_____RR : ____Rr
: ____rr
r
Rr
Red )
( ________
rr
White )
( ________
c.
Phenotype Ratio:
3
1
____Red
: ____White
Class Practice Problem
How to solve word problems
Tall (T) is dominant to Short (t) . A heterozygous
plant is crossed with a homozygous recessive
plant.
T = Tall
t = short
a. Complete the Punnet Square
b.List the genotype ratio of their offspring.
T
t
t
Tt
tt
t
Tt
0 TT : ___
2 Tt : ___tt
2
____
c.List the phenotype ratio of their offspring.
tt
____
2 Tall : ___
2 Short
First: Make a
cheat sheet
for the alleles
Second:
Underline the
parents
Third: Put into
Punnet
Forth: Write out
geno & pheno
Possibilities &
Count
• Complete
Punnett Practice 2