Genetics Complex Characteristics and Sex Influenced Traits Complex Characteristics Characteristics that are due to more than one gene Eye color hair color skin color height etc Most characteristics where there is a wide range of possibilities ID: 362485
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Slide1
Other Traits and Pedigrees
GeneticsSlide2
Complex Characteristics and Sex Influenced Traits
Complex Characteristics
Characteristics that are due to more than one gene.
Eye color, hair color, skin color, height, etc.Most characteristics where there is a wide range of possibilities. Sex Influenced TraitsNot the same as sex link traitsInfluenced traits are carried on autosomesThey are influenced due to the hormones that each gender producesMale 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. Slide3
Helpful Reminders
Complete Dominance
Can be done as an autosomal trait (A and a as alleles) or sex linked (X
R, 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 heterozygotesCodominanceTwo different letters for the alleles (R and B), both capital, look for spots, stripes
, or speckles
Incomplete Dominance
Same letter for the alleles (R and r), look for a blend (red + white = pink); 3 phenotypes
Dihybrid
FOIL!
Sex Linked
Use the sex chromosomes (
X
R
,
X
r
and Y)
Woman can
be
carriers; Men
cannot
be carriers, they either have it
o
r they don’t
Blood
Multiple alleles (I
A
, I
B
, and
i
o
); 4 phenotypesSlide4
Pedigrees
A way to follow a family lineage
Convenient for looking at traits as they pass on from parent to offspring, especially in the case of a lethal or debilitating disorderSlide5
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.Slide6
Steve
Amy
Sally
Jennifer
Josh
Allen
Christina
Ben
How many females are in this pedigree?
How many males are in this pedigree?
How many children do Steve and Amy have?
Who is the 2
nd
born child of Steve and Amy?
How is Sally related to Amy?
4
4
4
Allen
Sally is her granddaughterSlide7
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
Amy
Jennifer
Josh
Allen
Christina
Ben
Sally
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?
If they conceive another child, what would be the chance that they would also have
Tay
-Sachs?
They are carriers.
25%