Transcript Document

Notes: Pedigrees
A pedigree is a tool geneticists use to
trace the inheritance of traits in
humans.
A pedigree is a tool geneticists use to
trace the inheritance of traits in
humans.
= a circle represents a
female.
= a square represents a
male.
A circle or square that is
completely shaded in
indicates that person has the
trait.
A circle or square that is
not shaded in indicates that
the person does not have the
trait. This person has two
“normal” chromosomes.
= a circle or square that is
completely shaded in
indicates that person has the
trait.
= a circle or square that is
not shaded in indicates that
the person does not have the
trait. This person has two
“normal” chromosomes.
A half-shaded circle or
square indicates that person
is a carrier. (One “normal”
chromosome and one
“abnormal” chromosome –
the person will not show the
trait.)
= a half-shaded circle or
square indicates that person
is a carrier. (One “normal”
chromosome and one
“abnormal” chromosome –
the person will not show the
trait.)
A horizontal line connecting a male
and female represents marriage (or
mating).
A horizontal line connecting a male
and female represents marriage (or
mating).
A vertical line and bracket connect the
parents to their children.
A vertical line and bracket connect the
parents to their children.
Pedigree for Colorblindness
Colorblindness is a recessive trait, carried
on the X chromosomes.
Draw a pedigree with 2 generations if the
P generation is: X Y x X Xc
Pedigree for Colorblindness
Pedigree for Hairy toes:
Hairy toes is a recessive trait, carried on
the body chromosomes (NOT the sex
chromosomes).
Draw a pedigree with 3 generations if the P
generation is: Hh x Hh
REMEMBER: The shape is shaded in if it
HAS the trait!