Example Project
Confused? Here is an example
project on a power point.
1.
Key:
D = dominate allele, acondroplasia
d = recessive allele, normal stature
Genotype
Phenotype
DD (Homozygous dominate) = Dwarf and death before 1 year
Dd (heterozygous)
= Dwarf
dd (homozygous recessive) = Normal Stature
1.
Key:
D = dominate allele, acondroplasia
d = recessive allele, normal stature
Genotype
Phenotype
DD (Homozygous dominate) = Dwarf and death before 1 year
Dd (heterozygous)
= Dwarf
dd (homozygous recessive) = Normal Stature
2. Parents are both
dwarfs there for they
are both heterozygous.
1.
Key:
D = dominate allele, acondroplasia
d = recessive allele, normal stature
Genotype
Phenotype
DD (Homozygous dominate) = Dwarf and death before 1 year
Dd (heterozygous)
= Dwarf
dd (homozygous recessive) = Normal Stature
2. Parents are both
dwarfs there for they
are both heterozygous.
1.
Key:
D = dominate allele, acondroplasia
d = recessive allele, normal stature
Genotype
Phenotype
DD (Homozygous dominate) = Dwarf and death before 1 year
Dd (heterozygous)
= Dwarf
dd (homozygous recessive) = Normal Stature
D
D
d
d
2. Parents are both
dwarfs there for they
are both heterozygous.
Dd x Dd
D
d
D
D
d
d
D
d
D
d
D
DD
Dd
d
Dd
dd
Figure 1: A Punnett Square. Two
heterozygous parents were crossed.
Table 1: The frequency and probability of all the genotypes and phenotypes.
Offspring Genotype Phenotype
Frequency
Percentage
Homozygous
dominate (DD)
Dwarf and death
before 1 year
1: 4
25 %
Heterozygous (Dd)
Dwarf
2:4
50%
Homozygous
recessive (dd)
Normal stature
1:4
25%
D
d
D
DD
Dd
d
Dd
dd
Figure 1: A Punnett Square. Two
heterozygous parents were crossed.
Offspring Genotype
Phenotype
Frequency
Percentage
Homozygous
dominate (DD)
Dwarf and death
before 1 year
1: 4
25 %
Heterozygous (Dd)
Dwarf
2:4
50%
Homozygous
recessive
Normal stature
1:4
25%
Written Summary
SUMMARY OF
DISORDER
AND HOW IT
IS INHERITED
Genotypes
and
Phenotypes
of parents
The
probability
of certain
genotypes
and phone
According to the short article, acondroplasia or “dwarfism” is
a genetic disorder caused by a dominate allele (D). The key shows
that offspring with the homozygous dominate genotype (DD) are
dwarfs and sadly die before the age of one. Heterozygous
offspring (Hh) are dwarfed and homozygous recessive offspring
have a normal stature.
A heterzygous (Dd) couple came for genetic counseling. They
were both dwarfs. We conducted a Punnett Square to see what
the possibility of their offspring having the allele for dwarfism
would be. The completed Punnett Square can be seen in Figure 1.
The results are shown in Table 1. It was concluded that there was
a chance that 25% of the offspring would be homozygous
dominate (DD) and die before the age of one, 50% of the
offspring would be heterozygous (Dd) and be a dwarf and lastly,
25% of the offspring would be homozygous recessive and have a
normal stature.
Dr. Countryman and Dr. Scherben
Genetic Counseling Project
Acondroplasia “Dwarfism”
Key:
D = dominate allele, acondroplasia
d = recessive allele, normal stature
Genotype
Phenotype
DD (Homozygous dominate) = Dwarf and death before 1 year
Dd (heterozygous)
= Dwarf
dd (homozygous recessive) = Normal Stature
Written Summary
According to the short article, people with acondroplasia or “dwarfism” is
caused by a dominate allele (D). The key shows that offspring with the
homozygous dominate genotype (DD) are dwarfs and sadly die before the
age of one. Heterozygous offspring (Hh) are dwarfed and homozygous
recessive offspring have a normal stature.
A heterzygous (Dd) couple came for genetic counseling. They were
both dwarfs. We conducted a Punnett Square to see what the possibility
of their offspring having the allele for dwarfism would be. The completed
Punnett Square can be seen in Figure 1. The results are shown in Table 1.
It was concluded that there was a chance that 25% of the offspring would
be homozygous dominate (DD) and die before the age of one, 50% of the
offspring would be heterozygous (Dd) and be a dwarf and lastly, 25% of
the offspring would be homozygous recessive and have a normal stature.