Dowemakechoicesonthebasisofourownconsciousreflection?Arewe
personallyresponsibleforourpathinlife?Arewethemastersofourdestiny?
Or—doourgenesmakeusdoit?MAXIM’s residentClinicalNutritionist,
BROOKE BENSON CAMPBELL (BHSC Nut Med) investigates...
DESTINY B I O L O GY
OR
Do Our Genes Govern Our Fate?
foreyecolour,oneforhairtexture,onefor
skintoneandsoon.Weinheritedtwocopies
of eachgene(onefromeachparent)andthe
dominantallelewouldgoverntheresulting
feature.Itwasa simpletime,beforeNetflix,
gluten-freebread,iPhones,exoticsuperfoods
andTrump.Fast-forwarda fewdecades:
whileeatingoursmashedavoonGFtoast
aswescrollthroughInstagramslurping
onourMatchaLatteandembracingthe
presidentialTwitterfeed,wecomeacrossan
advertisementfora salivarytestthatanalyses
gene‘SNPs’andpromisesto provideinsight
intouniquepersonalitytraits,academic
potentialandlifespan—allforjust$300.
So,isthistestingthemodernequivalent
ofa crystalballora scientificexploration
intothefuture?Todeterminetheanswer,
weneedtostartbyunderstandingthe
scienceofepigenetics.
Epigenetics(whichmeans“overorabove
genetics”)is turningwhatwe’velongheld
trueaboutbiologicaldestinyandgenetic
predispositionupsidedown.Previous
studies,basedlargelyonstudiesoftwins,
havesuggestedthatmanyofourtraitsare
morethan50%inheritedandbasedin DNA
—theseincludeobediencetoauthority,
vulnerabilitytostressandrisk-taking
behaviour.Anotherhistoricalstudyofmore
than 800 setsof twinsin the UnitedStates
foundthatgeneticsweremoreinfluential
inshapingkeytraitsthana person’shome
environmentorsurroundings.Althoughit
remainstruethatourDNA—ourgenetic
code — provides the blueprint for ourF
lashbackto1979.Twoidentical
twins,JimSpringerandJimLewis,
werereunitedatage39,after
beingseparatedasone-month-
oldsandadoptedbydifferentfamilies.They
found,whencomparingstories,thatboth
hadmarriedanddivorceda womannamed
LindaandremarriedonenamedBetty.Both
hadinterestsincarpentryandmechanical
drawing,smokedSalemcigarettes,drove
pale-blueChevrolets,foundspellingdifficult
andhadworkedaspart-timedeputysheriffs.
BothalsonamedtheirfirstsonJamesAlan,
andtheirpet dogs‘Toy’.Thebasisof their
identitiesseemedtobewrittenintheirgenes.
Someofusmayfindthisstorydisturbing.
Weliketothinkthatwearethemastersof
ourdestiny,thatwemakechoicesonthe
basisofourownconsciousreflection,that
wearepersonallyresponsibleforourpath
inlife,thatthefutureisourstoshape.And
yetdoesthisstoryproveourfinaldecisions
arealreadypre-programmedingeneticcode?
Is ‘my genesmademe do it’ a viableget-out-
of-jail-freecatch-cry?
Nearly 100 yearsago,Freudwrotethat
‘biologyis destiny’but whenwe considerthe
latestdiscoveriesinthefieldofepigenetics
andbehaviouralscience,isthisstillaccurate?
Inthenatureversusnurturedebate,who
emergestriumphant?Let’swalkthegenetic
planktoanswertheage-oldquestion:do
ourgenesgovernourfate?
Whenwelearnedaboutgeneticsat
school,it seemedfairlystraightforward—
for every feature there existed a gene: one
physiologicalmakeup,recentstudies
havediscoveredthatthereissomething
elsethatiscontrollingeachandevery
gene—theepigenome.
Whileepigenomesdonotchangethe
DNA,theysitontopofeachgenome
anddirectthegenestoturnonoroff
dependingonenvironmentalchangesor
biologicaltriggers.Insimpleterms,if the
DNAisthehardware,theepigenomeisthe
software.Windowscanbeloadedontoa
MAC—thecomputerchipstaysinplace
(thesamegenome)but the softwarecan
bealtered.Thisnewdiscoverymeansthat
yourinheritedgeneticheritageisnotthe
primarydeterminantofyourhealth,illness
riskorlongevity.Inshort,yourgenotypeis
a predisposition,nota prediction.Itisthis
discoverythatmaybeabletohelpexplain
certainscientificmysteries:whycanone
memberofa pairofidenticaltwinsdevelop
asthmawhentheotherisfine,whyautism
strikesboysfourtimesasoftenasgirls,
orwhyextremechangesindietover
a shortperiodcouldleadtoextreme
changesinlongevity.
Whileepigeneticssoundscomplex,
oneofthewaysit altersthegenomeisfairly
simple.Researchershavefoundthatwhen
a singlemethylgroup(onecarbonatom
attachedto threehydrogenatoms)fastensto
a specificspotona gene,it canchangethe
gene—turningit onoroff.In2003,Duke
UniversityoncologistRandyJirtledisplayed
thepotentialeffectofDNAmethylationin
a groundbreaking experiment. He started