Homozygous: Two of the same
alleles of a gene—one from each
parent (U.S. National Library of
Medicine).
Heterozygous: Two different alleles
of a gene—one from each parent
(U.S. National Library of Medicine).
Punnett squares are used to calculate the
probability for the traits of the offspring.
Homozygous
Dominant
Each parent contributes
homozygous dominant alleles.
Calculate the offspring possibilities
by completing the Punnett square.
100% of the offspring will be
heterozygous (YG).
Heterozygous vs.
Homozygous Offspring
Each
parent
contributes
One
parent
contributes
oneone
dominant
recessive
(a)
dominant(A)
andand
oneone
recessive
allele
allele (heterozygous).
(heterozygous);
the other parent
contributes two recessive alleles
(homozygous).
Dennis O’Neil with Palomar College (1997-2012) expressed the following:
If
both parents
are carriers
of College
the recessive
allele for
a disorder,
of their
Dennis
O’Neil with
Palomar
(1997-2012)
expressed
theall
following:
children
will face
the following
inheriting
it: disorder, their
If one parent
is a carrier
and theodds
otherofhas
a recessive
25%
chance
having
the recessive
children
willof
have
the following
oddsdisorder
of inheriting it:
50%
chance
of
being
a
healthy
carrier
50% chance of being a healthy carrier
25%
beingthe
healthy
anddisorder
not have
50% chance
chance of
having
recessive
the recessive allele at all
Calculate the ratios of
offspring eye color for
each scenario.
2. Parent
1.
Parent11has
hasbrown
browneyes
eyes(Bb);
(BB);
parent
2 has2brown
eyes
(Bb).
parent
has blue
eyes
(bb).
100% of the offspring will have
75% of the offspring will have brown eyes.
brown eyes, but will carry the
•25% will be homozygous dominant for
recessive blue eye trait.
brown eye color (BB).
•50% will be heterozygous (Bb).
All offspring will be
25% of the offspring will have blue eyes
heterozygous (Bb).
and will be homozygous dominant for
blue eye color (bb).
http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/GP/Definition.html
http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/GP/Relationship.html