Lecture 9

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Unformatted text preview: 3/6/10 Pedigrees
 Many
traits
(hair
color,
eye
color,
and
facial
structure)
exhibit
 incomplete
dominance
or
codominance
 –  traits
result
from
several
genes
interac:ng
with
each
other
and
 ac:ng
simultaneously
 Polygenic
traits:
phenotype
results
from
interac:on
of
many
genes,
not
 the
expression
of
just
one
 –  mul$factorial
traits:
meaning
polygenic
traits
that
are
also
 influenced
by
environment
 –  body
type,
muscular
development,
fat
deposi:on,
and
height
are
 all
mul:factorial
traits
 Traits
 Codominance
 Sex
Chromosomes
 Humans
have
one
pair
of
chromosomes,
called
the
sex
chromosomes
 –  do
not
match
in
terms
of
size
or
content
 –  the
sex
chromosomes
include
the
large
X
chromosome
and
the
 smaller
Y
 These
two
determine
gender
 –  if
a
Y
chromosome
is
present
during
development
(XY),
the
fetus
 will
become
a
male
 –  if
there
is
no
Y
present
(XX),
the
fetus
becomes
female
 Any
chromosome
other
than
the
sex
chromosomes,
(X
and
Y)
are
 termed
autosomal
 Sex
chromosomes
(X
and
Y)
carr...
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This note was uploaded on 10/27/2010 for the course BIOL 125 taught by Professor Klein during the Spring '10 term at CUNY Hunter.

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