Transcript Heterozygous vs. Homozygous

 Contains

both dominant AND recessive alleles
Notice, one capital letter and one lower case
letter
 Examples:
Bb
Aa
Zz
Yy
Mm
 Contains
only dominant OR recessive alleles
 Homozygous dominant:

Both Capital letters
BB
AA
ZZ
YY
 Homozygous

recessive:
Both lower case letters
bb
aa
zz
yy
 In
garden peas, the allele for yellow (Y) is
dominant to the allele for green (y)
 Write the genotype for homozygous dominant

YY
 Write

yy
 Write

the genotype for homozygous recessive
the genotype for heterozygous
Yy or yY (usually written capital letter first)
Yy
YY
yy
 In
fruit flies, the allele for white eyes (r) is
recessive to the allele for red eyes (R)
 Write the genotype for homozygous dominant

RR
 Write

the genotype for heterozygous
Rr
 Show
a cross between the
homozygous dominant and the
homozygous recessive
 In
cats, the allele for yellow eyes (E) is
dominant to the allele for blue eyes (e)
 Write the genotype for heterozygous
 Ee
 Write
the genotype for homozygous
recessive
 ee
 Show
a cross between two
heterozygous
 In
vampires, the allele for long fangs(F) is
dominant to the allele for short fangs (f)
 Write the genotype for a homozygous
dominant vampire

FF
 Write
the genotype for a homozygous
recessive vampire

Ff
 Show
a cross between two heterozygous
vampires
 In
werewolves, the allele for long hair (h) is
recessive to the allele for short hair (H)
 Write the genotype for homozygous dominant
hair

HH
 Write

Hh
the genotype for heterozygous