FS2 VARIATIONS IN THE GENETIC CODE
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
DNA sta ds fo deo i o u lei a id a d fo s the i st u io ook of ou odies. It is ade up of
e lo g hai s of fou asi uildi g lo ks alled ases. The ases a e a ed Ade i e A , Gua i e G ,
Th i e T a d C tosi e C . Like a ook, the e a e ha ges i the
o ds . “o e ha ges a e
ha less ut othe s a afe t ou health.
I su
ay
DNA p o ides the i st u io s fo the ells that
ake up ou
E e yo e’s DNA is so e hat dife e t; a iaio s i ou DNA
So e DNA a iaio s a e i he ited f o
othe s a e a ui ed th oughout life
DNA a iaio s that ha e o ad e se efe ts o ou
populaio a e alled poly o phis s
DNA a iaio s that do afe t the fu io of the p otei
ote a e alled utaio s.
ody
ake us u i ue
ou pa e t/s, so e appea f o
DNA AND GENES
Ou DNA is ade up of se io s that ode fo
p otei s, ou ge es, a d se io s that do ot
ode fo p otei s. P otei s do the o k i ou
ells a d these a e e i po ta t fo o al ell
fu io a d ou health. Ou p otei
odi g
DNA, ou ge es, do ot o tai
u h a iaio .
“e io s of ou DNA that do ot ode fo p otei
o tai
u h
o e a iaio . We do ot
u de sta d all the fu io s of these o -p otei
odi g se io s of DNA, ut e k o se io s
a e i po ta t fo o t olli g ou ge es.
People ge e all ha e the sa e u e a d
se ue e of p otei odi g ge es so that the
sa e essages a e se t to the od . Ho e e ,
the e a e s all a iaio s et ee i di iduals
i the i fo aio
o tai ed i spe ii DNA
odes. Me e s of the sa e fa il te d to e
o e si ila i thei ge es tha u elated
i di iduals.
A e a ple of this is e e olou . E e o e has
t o ge es that dete i e e e olou , ut
ha ges i these ge es a
ake e e olou a ,
this is h so e people ha e lue e es, so e
o , so e hazel. The sa e ge e a se d
dife e t essages e ause of a iaio s i the
essages.
“i ila l , the e a e s all a iaio s i ou
DNA that a afe t ho ou odies g o a d
de elop.
i th hile
ells a d o u f e ue tly i the
ade f o
a ge e a d o u less
Ge e all these a ia ts do ot ha e a i pa t
o ou health a d a e alled eut al a ia ts o
poly o phis s poly ea s a ; orphis s
ea s fo s . Pol o phis s a e uite o
o
i the DNA ode.
DNA VARIATIONS
Va iaio s i the DNA ode a o u du i g ou
life fo a a iet of easo s i ludi g e posu e to
adiaio , e tai he i als,
ha e o othe
u k o
fa to s. Agei g is o e of the ost
o
o auses of ge ei a iaio . Th oughout
ou life, ells g o , di ide a d die. This ea s
ells a d thei DNA a e opied o e a d o e
agai . As e age, ou ells ake istakes hi h
a ot e o e ted as ei ie tl as i ou ge
people. DNA ha ges a u ulate a d a ha e
a i pa t o ou health.
“o e DNA ha ges do ot see to ake a
dife e e to the a a ell fu io s. These
t pes of ha ges a e p o a l uite o
o .
Othe DNA ha ges a e asso iated ith a
i eased ha e of de elopi g a health
o diio , fo e a ple dia etes o a e .
“o e DNA ha ges a
ea the i st u io s a e
i o e t so a fault p otei is ade o the
o t ol s it h is ha ged. A a iaio i a DNA
site that eates a fault is alled a utaio .
These a e uite a e.
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
A DNA utaio a ause a p o le fo o e ell
t pe ut ot a othe , si e ot all ells use all of
the possi le p otei s. Whe a DNA ha ge auses
a fault p otei i ells that eed that p otei , it
usuall esults i a disease state o s pto a d
is ote e og ised as a ge ei o diio .
GENE MUTATIONS
E e o e is o
ith se e al ge e utaio s i
thei
,
o so total u e of ge e pai s.
Depe di g o othe fa to s, these utaio s a
o a ot ause a health p o le s.
Most of the i e, utaio s ause o p o le
e ause ge es o e i pai s. This ea s that
e e
he o e ge e op has a utaio , the
othe ge e op is o ki g a d a sill se d the
ight essage to the od . These a e k o
as
e essi e ge e utaio s.
I so e ases ho e e , it is esse ial to ha e oth
ge e opies o ki g o e tl as the a ou t of
ge e p odu t a e ii al. “o i these ases,
e e though o l o e op of the ge e has a
utaio , a d the othe is o ki g, a health
p o le
a sill o u . These a e k o
as
do i a t ge e utaio s.
I he ited
As
e io ed a o e, e e o e is o
ith
se e al ge e utaio s i thei
,
o so total
u e of ge e pai s. These a e usuall passed
do i the fathe s spe o the othe s egg.
O e that hild has the utaio , the ill ha e it
fo life a d a also pass it o to thei futu e
hild e . This is a i he ited utaio see Figure
. .
Figure . sho s a utaio ei g passed do
th ough the spe o l . I he ited utaio s a
e passed do
o l the fathe , o l the
othe o
oth pa e ts. The a i
hi h the
utaio /s ill afe t the hild ill depe d o
othe fa to s as
ell as the
utaio /s
the sel es.
“pe
a d egg ells a e alled ge
ells a d
the efo e utaio s that a e p ese t i the ge es
of the egg o spe a e alled ge
ell o ge li e utaio s.
If ou ha e i he ited a ge e utaio f o o e o
oth of ou pa e ts, ou ill also possi l pass it
o to ou futu e hild e
Othe
utaio s ake a pe so sus epi le to
pa i ula o diio s ut the
ill e e de elop
the p o le u less the a e e posed to pa i ula
e i o e tal t igge s. These a e k o
as
ulifa to ial or sus epi ility ge e utaio s.
I so e ases, ha i g a pa i ula ha ge i ou
DNA a e e ei ial to a pe so . Fo e a ple, i
ega ds to the o diio
alled thalassae ia,
esea h has sho
that people ho ha e o e
op of thei thalassae ia ge e o ki g a d the
othe ith a utaio a e less likel to de elop
ala ia.
INHERITED, SPORADIC AND ACQUIRED
MUTATIONS
Mutaio s a o u i a u e of a s i a
pe so . The a e i he ited f o o e o oth
pa e ts, the a o u fo the i st i e i a
pe so fo o appa e t easo spo adi o the
a o e a out i the od o e i e a ui ed .
Figu e . : I herita e of a utaio fro a ger
ell egg
or sper . The egg fro the other is arryi g a orki g
opy of the ge e. The sper fro the father is arryi g a
faulty opy of the ge e. Their ofspri g ill ha e oth a
faulty opy a d a orki g opy of the ge e i all the ells of
their ody. This ay also o ur i the re erse situaio .
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
Figu e . : Mutaio s a o ur ery early duri g ferilisaio of the egg a d sper . The
ut all future ells of the a y ha e the utaio .
Spo adi
Whe a health o diio is aused
a ge e
utaio that appea s fo the i st i e i a
fa il , it is said to e spo adi . “po adi ge ei
o diio s o e a out he a spo ta eous
utaio o u s at the i e of fe ilisaio .
Although it is ot i he ited f o o e of ou
pa e ts, ou a sill pass it o to ou futu e
hild e . You spe
o eggs ill o
o tai
this utaio . see Figure . .
utaio is ot i herited
Ac ui ed
DNA ha ges a o e a out due to thi gs e
e pe ie e du i g ou life. Fo e a ple,
adiaio
p odu ed
the su , e tai
he i als, o othe e i o e tal fa to s.
DNA ha ges a also o u as ou ells a e
opied to e a le us to g o o epai da aged
ells th oughout life as e age.
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
Figu e . : Mutaio s i so ai
ells
ay o ly afe t o e spe ii area su h as the reast issue.
Although the od has a ei ie t s ste to
epai these a iaio s i the DNA as the o u ,
so ei es the e is a eakdo
i the ell s
epai s ste .
Bod ells ot the egg o spe
a e alled
so ai ells a d the efo e a utaio that
o u s i a so ai
ell is alled a so ai
utaio .
If a a iaio to the DNA o u s a d is ot
epai ed, it ill e opied i to all the ells a isi g
f o that ell see Figure . .
I Figure . , the so ai utaio has a ise i a
ge e i a ell of the east issue o l a d so
a ot e passed o to a hild.
As ith othe DNA a iaio s, if the ge e essage
e o es fault , a
utaio is said to ha e
o u ed.
A so ai utaio ill o l afe t the pa t of the
od i that pa i ula i di idual. “o ai ells a e
the efo e ot passed do
to hild e o
i he ited.
.ge ei s.edu.au
Updated
Page of
Ju e
6
DNA sta ds fo deo i o u lei a id a d fo s the i st u io ook of ou odies. It is ade up of
e lo g hai s of fou asi uildi g lo ks alled ases. The ases a e a ed Ade i e A , Gua i e G ,
Th i e T a d C tosi e C . Like a ook, the e a e ha ges i the
o ds . “o e ha ges a e
ha less ut othe s a afe t ou health.
I su
ay
DNA p o ides the i st u io s fo the ells that
ake up ou
E e yo e’s DNA is so e hat dife e t; a iaio s i ou DNA
So e DNA a iaio s a e i he ited f o
othe s a e a ui ed th oughout life
DNA a iaio s that ha e o ad e se efe ts o ou
populaio a e alled poly o phis s
DNA a iaio s that do afe t the fu io of the p otei
ote a e alled utaio s.
ody
ake us u i ue
ou pa e t/s, so e appea f o
DNA AND GENES
Ou DNA is ade up of se io s that ode fo
p otei s, ou ge es, a d se io s that do ot
ode fo p otei s. P otei s do the o k i ou
ells a d these a e e i po ta t fo o al ell
fu io a d ou health. Ou p otei
odi g
DNA, ou ge es, do ot o tai
u h a iaio .
“e io s of ou DNA that do ot ode fo p otei
o tai
u h
o e a iaio . We do ot
u de sta d all the fu io s of these o -p otei
odi g se io s of DNA, ut e k o se io s
a e i po ta t fo o t olli g ou ge es.
People ge e all ha e the sa e u e a d
se ue e of p otei odi g ge es so that the
sa e essages a e se t to the od . Ho e e ,
the e a e s all a iaio s et ee i di iduals
i the i fo aio
o tai ed i spe ii DNA
odes. Me e s of the sa e fa il te d to e
o e si ila i thei ge es tha u elated
i di iduals.
A e a ple of this is e e olou . E e o e has
t o ge es that dete i e e e olou , ut
ha ges i these ge es a
ake e e olou a ,
this is h so e people ha e lue e es, so e
o , so e hazel. The sa e ge e a se d
dife e t essages e ause of a iaio s i the
essages.
“i ila l , the e a e s all a iaio s i ou
DNA that a afe t ho ou odies g o a d
de elop.
i th hile
ells a d o u f e ue tly i the
ade f o
a ge e a d o u less
Ge e all these a ia ts do ot ha e a i pa t
o ou health a d a e alled eut al a ia ts o
poly o phis s poly ea s a ; orphis s
ea s fo s . Pol o phis s a e uite o
o
i the DNA ode.
DNA VARIATIONS
Va iaio s i the DNA ode a o u du i g ou
life fo a a iet of easo s i ludi g e posu e to
adiaio , e tai he i als,
ha e o othe
u k o
fa to s. Agei g is o e of the ost
o
o auses of ge ei a iaio . Th oughout
ou life, ells g o , di ide a d die. This ea s
ells a d thei DNA a e opied o e a d o e
agai . As e age, ou ells ake istakes hi h
a ot e o e ted as ei ie tl as i ou ge
people. DNA ha ges a u ulate a d a ha e
a i pa t o ou health.
“o e DNA ha ges do ot see to ake a
dife e e to the a a ell fu io s. These
t pes of ha ges a e p o a l uite o
o .
Othe DNA ha ges a e asso iated ith a
i eased ha e of de elopi g a health
o diio , fo e a ple dia etes o a e .
“o e DNA ha ges a
ea the i st u io s a e
i o e t so a fault p otei is ade o the
o t ol s it h is ha ged. A a iaio i a DNA
site that eates a fault is alled a utaio .
These a e uite a e.
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
A DNA utaio a ause a p o le fo o e ell
t pe ut ot a othe , si e ot all ells use all of
the possi le p otei s. Whe a DNA ha ge auses
a fault p otei i ells that eed that p otei , it
usuall esults i a disease state o s pto a d
is ote e og ised as a ge ei o diio .
GENE MUTATIONS
E e o e is o
ith se e al ge e utaio s i
thei
,
o so total u e of ge e pai s.
Depe di g o othe fa to s, these utaio s a
o a ot ause a health p o le s.
Most of the i e, utaio s ause o p o le
e ause ge es o e i pai s. This ea s that
e e
he o e ge e op has a utaio , the
othe ge e op is o ki g a d a sill se d the
ight essage to the od . These a e k o
as
e essi e ge e utaio s.
I so e ases ho e e , it is esse ial to ha e oth
ge e opies o ki g o e tl as the a ou t of
ge e p odu t a e ii al. “o i these ases,
e e though o l o e op of the ge e has a
utaio , a d the othe is o ki g, a health
p o le
a sill o u . These a e k o
as
do i a t ge e utaio s.
I he ited
As
e io ed a o e, e e o e is o
ith
se e al ge e utaio s i thei
,
o so total
u e of ge e pai s. These a e usuall passed
do i the fathe s spe o the othe s egg.
O e that hild has the utaio , the ill ha e it
fo life a d a also pass it o to thei futu e
hild e . This is a i he ited utaio see Figure
. .
Figure . sho s a utaio ei g passed do
th ough the spe o l . I he ited utaio s a
e passed do
o l the fathe , o l the
othe o
oth pa e ts. The a i
hi h the
utaio /s ill afe t the hild ill depe d o
othe fa to s as
ell as the
utaio /s
the sel es.
“pe
a d egg ells a e alled ge
ells a d
the efo e utaio s that a e p ese t i the ge es
of the egg o spe a e alled ge
ell o ge li e utaio s.
If ou ha e i he ited a ge e utaio f o o e o
oth of ou pa e ts, ou ill also possi l pass it
o to ou futu e hild e
Othe
utaio s ake a pe so sus epi le to
pa i ula o diio s ut the
ill e e de elop
the p o le u less the a e e posed to pa i ula
e i o e tal t igge s. These a e k o
as
ulifa to ial or sus epi ility ge e utaio s.
I so e ases, ha i g a pa i ula ha ge i ou
DNA a e e ei ial to a pe so . Fo e a ple, i
ega ds to the o diio
alled thalassae ia,
esea h has sho
that people ho ha e o e
op of thei thalassae ia ge e o ki g a d the
othe ith a utaio a e less likel to de elop
ala ia.
INHERITED, SPORADIC AND ACQUIRED
MUTATIONS
Mutaio s a o u i a u e of a s i a
pe so . The a e i he ited f o o e o oth
pa e ts, the a o u fo the i st i e i a
pe so fo o appa e t easo spo adi o the
a o e a out i the od o e i e a ui ed .
Figu e . : I herita e of a utaio fro a ger
ell egg
or sper . The egg fro the other is arryi g a orki g
opy of the ge e. The sper fro the father is arryi g a
faulty opy of the ge e. Their ofspri g ill ha e oth a
faulty opy a d a orki g opy of the ge e i all the ells of
their ody. This ay also o ur i the re erse situaio .
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
Figu e . : Mutaio s a o ur ery early duri g ferilisaio of the egg a d sper . The
ut all future ells of the a y ha e the utaio .
Spo adi
Whe a health o diio is aused
a ge e
utaio that appea s fo the i st i e i a
fa il , it is said to e spo adi . “po adi ge ei
o diio s o e a out he a spo ta eous
utaio o u s at the i e of fe ilisaio .
Although it is ot i he ited f o o e of ou
pa e ts, ou a sill pass it o to ou futu e
hild e . You spe
o eggs ill o
o tai
this utaio . see Figure . .
utaio is ot i herited
Ac ui ed
DNA ha ges a o e a out due to thi gs e
e pe ie e du i g ou life. Fo e a ple,
adiaio
p odu ed
the su , e tai
he i als, o othe e i o e tal fa to s.
DNA ha ges a also o u as ou ells a e
opied to e a le us to g o o epai da aged
ells th oughout life as e age.
.ge ei s.edu.au
Updated
Page of
Ju e
6
Fa t Sheet 2 | VARIATIONS IN THE GENETIC CODE
Figu e . : Mutaio s i so ai
ells
ay o ly afe t o e spe ii area su h as the reast issue.
Although the od has a ei ie t s ste to
epai these a iaio s i the DNA as the o u ,
so ei es the e is a eakdo
i the ell s
epai s ste .
Bod ells ot the egg o spe
a e alled
so ai ells a d the efo e a utaio that
o u s i a so ai
ell is alled a so ai
utaio .
If a a iaio to the DNA o u s a d is ot
epai ed, it ill e opied i to all the ells a isi g
f o that ell see Figure . .
I Figure . , the so ai utaio has a ise i a
ge e i a ell of the east issue o l a d so
a ot e passed o to a hild.
As ith othe DNA a iaio s, if the ge e essage
e o es fault , a
utaio is said to ha e
o u ed.
A so ai utaio ill o l afe t the pa t of the
od i that pa i ula i di idual. “o ai ells a e
the efo e ot passed do
to hild e o
i he ited.
.ge ei s.edu.au
Updated
Page of
Ju e
6