Transcript Genetics Fill-In Notes Part 2

Genetics Fill-In Notes Part 2
Mrs. Kooiman
Incomplete Dominance
 When
a cross between organisms
with two different phenotypes
produces offspring with a third
phenotype that is a blend of the
parental traits.
Incomplete Dominance
Example: Red and White flowered plants
that produce pink offspring.
 In this case, you can use two different
letters in the Punnett Square.
 Red Flowered Plant (RR) X White
Flowered Plant (WW)
 The heterozygous offspring are Pink (RW)

Incomplete Dominance
R
R
W
RW
RW
W
RW
RW
Co-Dominance
 A cross
between organisms with
two different phenotypes
produces offspring with a third
phenotype in which both of the
parental traits appear together.
Co-Dominance
Example: Black and white haired horses
produce offspring with a mix of black a
white fur (or spots)
 Black haired horse (BB) X White haired
horse (WW)
 The heterozygous offspring are black and
white (BW)

Co-Dominance
B
B
W
BW
BW
W
BW
BW
Pedigree Diagram
 A diagram
of family history that
shows how a trait is inherited over
several generations.

Similar to a family tree that can help to
determine if children will inherit a disorder.
Pedigree Diagram
Sex-Linked Traits



A trait whose allele is located on the xchromosome. Most are recessive.
Since males only have one X-chromosome (XY) a
male who carries a recessive allele will have the
disorder.
Females have two X-chromosomes (XX) and will
ONLY show the disorder if they inherit both
recessive alleles. Just like how you normally do
not see a recessive trait unless the genotype is
homozygous recessive. Otherwise, the
normal/dominant allele will mask the recessive
allele.