Transcript Other Traits and Pedigrees

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Other Traits and Pedigrees
Genetics
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Complex Characteristics and Sex
Influenced Traits
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Complex Characteristics
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Characteristics that are due to more than one gene.
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Eye color, hair color, skin color, height, etc.
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Most characteristics where there is a wide range of
possibilities.
Sex Influenced Traits
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Not the same as sex link traits
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Influenced traits are carried on autosomes
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They are influenced due to the hormones that each
gender produces
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Male Pattern Baldness – A trait where males start
going. This trait is actually a dominant trait and only
one allele is needed to have it, in men. However, it is
sex influenced. Women actually need 2 dominant
alleles in order to express this trait.
+ Helpful Reminders
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Complete Dominance
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Codominance
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FOIL!
Sex Linked
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Same letter for the alleles (R and r), look for a blend (red + white = pink); 3 phenotypes
Dihybrid
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Two different letters for the alleles (R and B), both capital, look for spots, stripes, or
speckles
Incomplete Dominance
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Can be done as an autosomal trait (A and a as alleles) or sex linked (XR, Xr and Y).
Only two phenotypes exist and one can cover up the other.
If it is autosomal both men and woman can be hybrid, carriers, or heterozygotes
Use the sex chromosomes (XR, Xr and Y)
Woman can be carriers; Men cannot be carriers, they either have it or they don’t
Blood
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Multiple alleles (IA, IB, and io); 4 phenotypes
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Pedigrees
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A way to follow a family lineage
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Convenient for looking at traits as they pass on from parent to
offspring, especially in the case of a lethal or debilitating
disorder
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Pedigrees
A circle represents a female.
A shaded in circle represents a female that
has a specific trait.
A square represents a male.
A shaded in square represents a male that
has a specific trait.
A horizontal line indicates two individuals that
have produced offspring
A vertical line coming down indicates the
offspring that they have produced.
Siblings are connected by a horizontal line
that drops down into vertical lines.
Offspring go in birth order.
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Steve
Josh
Allen
Amy
Jennifer
How many females are in this pedigree?
Ben
Christina
4
Sally
How many males are in this pedigree?
4
How many children do Steve and Amy have?
4
Who is the 2nd born child of Steve and Amy?
Allen
How is Sally related to Amy?
Sally is her granddaughter
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Tay-Sachs Disease is an autosomal recessive disorder. It is caused by the
absence of the enzyme Hex-A. This causes cells to become damaged. This will
result in progressive neurological disorders eventually leading to death.
Steve
Josh
Allen
Amy
Jennifer
Ben
Six months are Ben and Christina had Sally, they discovered that
Sally had Tay-Sachs disease. Since it is an autosomal recessive
disorder:
What does this mean about Ben and Christina?
Christina
Sally
They are carriers.
If they conceive another child, what would be the chance that
they would also have Tay-Sachs?
25%