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Deducing genotypes
IB Biology
Jin Young Huh
Pedigree Charts
 Shows
all the known
phenotypes
 Used to deduce whether a
character is
caused by a dominant or
recessive allele
 sex linked

 Deduce
genotype of individuals
Pedigree Chart
Taste blindness
Pedigree Chart

A family
pedigree for
an X-linked
recessive
disease


ex) red-green
colour blindness
No male to
male disease
transmission
Test Cross

In a test cross
an individual
that might be
heterozygous
is crossed with
an individual
that is
homozygous
recessive.
Test Cross Example: Incomplete
dominance


One allele for
a specific
trait is not
completely
dominant
over the
other allele
Combined
phenotype