Traits can be inherited!
Arlene Chambers

Traits are inherited through genes

Traits are inherited through genes
• Genes are on chromosomes http://www.biotechnologyonline.gov.au

Traits are inherited through genes
• Genes are on chromosomes
• One chromosome inherited from each parent http://www.biotechnologyonline.gov.au

Traits are inherited through genes
• Genes are on chromosomes
• One chromosome inherited from each parent
• We have two copies of each chromosome, and thus, two copies of each gene http://www.biotechnologyonline.gov.au

Different versions of genes are alleles

Different versions of genes are alleles
For each gene, you might have…
2 different alleles

Different versions of genes are alleles
For each gene, you might have…
2 different alleles
2 of the same allele

Different versions of genes are alleles
For each gene, you might have…
2 different alleles 2 of the same allele
Combinations of alleles determine what traits you have

Can you roll your tongue ?

Can you roll your tongue ?
Yes! You carry a copy of the dominant allele.
OR

Can you roll your tongue ?
Yes! You carry a copy of the dominant allele.
No! You have two copies of the recessive allele.
OR

Can you roll your tongue ?
Yes! You carry a copy of the dominant allele.
No! You have two copies of the recessive allele.
OR
If you inherit both alleles, the dominant one is expressed.

Can you roll your tongue ?
Yes! You carry a copy of the dominant allele.
No! You have two copies of the recessive allele.
OR
If you inherit both alleles, the dominant one is expressed.
Dominant does NOT mean more common!

The Genetic Wheel

Single-gene Traits
L – dimples
(dominant)
ll – no dimples
(recessive)

If you have laugh dimples, your genetic wheel will look like this…
L l l

Single-gene Traits
T – can roll tongue
(dominant)
tt – cannot roll tongue
(recessive)

Single-gene Traits
C – left thumb on top
(dominant)
cc – right thumb on top
(recessive)

Single-gene Traits
P – pinkies bend away
(dominant)
pp – pinkies are straight
(recessive)

Single-gene Traits
E – ear lobe is free
(dominant)
ee – ear lobe is attached
(recessive)

Single-gene Traits
W – has widow ’ s peak
(dominant)
ww – no widow ’ s peak
(recessive)

Single-gene Traits
B – thumb is straight
(dominant)
bb – thumb bends back
(recessive)

ww bb 32
32

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Genetic Wheel Results
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There are 128 possible combinations from the
7 traits illustrated on the genetic wheel.
Are you the same as anyone else?

Genetic Wheel Results
32
There are 128 possible combinations from the
7 traits illustrated on the genetic wheel.
Are you the same as anyone else?
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If this much genetic variation exists in traits that are visible, imagine how different we all are in ways that we can ’ t see!