Download Genes are…

GENETICS WITH A SMILE
Define
Explain:
dominant and recessive traits
homozygous
heterozygous
genotype
phenotype
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Creating your Smiley Face offspring:
1. flip coins to determine their physical
traits.
2. match traits on sheet to determine
what your offspring look like.
3. flip coins to determine male or female.
4. sketch Smiley; in Tech class you will use
Word to computer generate sketch.
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Genes are…not these!
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Where do they come from?
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How many does each cell have?
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Where do we find them?
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Dominant gene-one that always shows up.
Write it as a capital letter;
example: B for brown hair
Recessive gene-one that is hidden when
the other copy of the gene contains a
dominant trait. Only shows up when there
is no dominant gene present.
 Write it as a lower case letter;
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example: b for blond hair
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What if an offspring inherits one dominant gene
from their mother and one dominant gene from
their father?
Example: BB for brown hair
We call that being HOMOZYGOUS dominant
because you have two genes that are the same.
Two capital letters!
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Both the same trait from parents that
always shows up
use capital letter
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Brown hair from mother
B
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Brown hair from father
B
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What if an offspring inherits one
recessive gene from their mother and
one recessive gene from their father?
Example: bb for blond hair
We call that being homozygous
recessive. Two genes the same; use
lower case.
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Both same trait but doesn’t show up
if dominant trait is present.
blond hair from mother
blond hair from father
bb
b
b
 What
if an offspring inherits one
dominant gene from one parent and
one recessive gene from the other
parent?
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Example: Bb
 What
do you think we would call this?
Heterozygous
Dominant!!
Bb
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Those capital and lower case letters
you just learned about…tell what your
genes are.
 BB
 bb
 Bb
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Those physical traits that you inherited from
your parents:
Brown hair
Blue eyes
Red nose…oops, sorry!
Right handedness
Color blindness
Straight hairline
2 pennies; 1 for each parent; male-female
PENNIES ARE MARKED M AND F
1. Flip both coins at the same time for each trait on
your sheet.
2. HEADS= DOMINANT TRAIT
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TAILS= RECESSIVE TRAIT
3. Circle the capital or lower case letter on your
sheet.
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4. Write in the Genotype…CC, cc, Cc
5. Write in the Phenotype…oval face, round
head.
look at the Smiley Face Traits sheet.
6. This will help you create your Smiley face
sketch.
7. You will recreate this sketch on your
laptop in Tech class.
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Traits are contained in our genes; also
referred to as ALLELLES