Download Rules for Writing Genotypes:

Rules for Writing Genotypes:
1. Dominant gene is always written as
a capital letter. It’s always first in
the gene pair.
Black is dominant over white.
B=black coat
b=white coat
2. The first letter of the dominant trait
is the letter used to represent both
the dominant and recessive alleles.
3. The recessive allele is always written
as a lower case letter.
4. Alleles for a particular trait always
occur in pairs. One allele from the
father and one allele from the
mother.
Examples:
1. Write the genotype of a heterozygous
brown-eyed cat. Brown is dominant
over blue. B=Brown Eyes b=blue
eyes
Bb is its genotype
2. What is the genotype of a blue-eyed
cat? bb is a blue eyed cat
3. What is the genotype of a
homozygous brown-eyed cat?
BB is a homozygous brown-eyed cat
If having dimples is dominant over not
having dimples.
D=Dimples
d=no dimples
a) DD
b)Dd
c)dd
If long hair is dominant over short hair
L=Long
l=short
Ll
LL
ll
F=Freckles
f=no freckles
a)FFCC
b)ffcc
B=Black fur
b=White fur
C=Curly hair
c=straight hair
c)Ffcc
d) FfCc
BB x bb
B
B
Bb
Bb
Bb
Bb
Bb
Bb
Bb
Bb