Recently
,
research
into
____________________
development
has
given
us
an
even
better
insight
into
____________________
major
structural
changes
might
occur
in
a
given
population
of
organisms
.
We
now
understand
that
there
are
two
major
types
____________________
genes
:
developmental
and
"
housekeeping
"
genes
.
Developmental
genes
are
those
that
are
expressed
during
embryonic
development
,
and
their
proteins
____________________
the
____________________
,
skeletal
development
,
organ
placement
,
and
overall
form
of
the
developing
animal
.
In
____________________
,
"
housekeeping
"
genes
are
expressed
during
the
animal's
daily
life
to
generate
proteins
which
keep
the
cells
,
tissues
,
and
organs
in
the
body
functioning
properly
.
____________________
you
might
suspect
,
mutations
in
developmental
genes
can
____________________
radical
consequences
for
body
form
and
function
,
whereas
mutations
in
"
housekeeping
"
genes
tend
to
____________________
the
health
and
reproductive
success
of
the
post
-
embryonic
animal
.
