Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
PATTERNS IN THE DISTRIBUTION OF LACTASE PERSISTENCE
OVERVIEW
ThisactivityservesasasupplementtothefilmGotLactase?TheCo-evolutionofGenesandCulture.Students
analyzedataobtainedfrompublishedlactase-persistencestudiesinvolvingmanypopulationssampledaround
theworld.Theactivityinvolvescalculatingpercentages,drawingpiecharts,plottingthepiechartsonaworld
map,andanalyzingthedata.Thislessonprovidesaninterdisciplinaryapproachtostudyinglactasepersistence,
connectingbiologicalconceptsanddataanalysistoworldgeographyandculture.
KEYCONCEPTSANDLEARNINGOBJECTIVES
• Humans,likeallspecies,evolveandadapttotheirenvironmentthroughnaturalselection.Lactase
persistenceisanexampleofanadaptationinsomegroupsofpeople.
• Boththephysicalandculturalenvironmentcanaffectselectivepressures.Thepracticeofdairyingprovided
anenvironmentinwhichlactasepersistencewasadvantageous.
• Combiningdatafrommultiplestudiesisasciencepracticeusedtosearchforpatternsnotevidentfrom
smallerindividualstudies.
Aftercompletingthisactivity,studentsshouldbeableto
• interpretdatapresentedintableformandextrapolateinformation;
• calculatefrequenciesandgraphthedatainpiecharts;
• interpretdatafromdifferentresearchstudiestoinferglobaldistributionpatternsinthedata;and
• makeclaimsbasedonscientificevidenceandusescientificreasoningtosupporttheclaims.
CURRICULUMCONNECTIONS
Curriculum
NGSS(April2013)
CommonCore(2010)
APBiology(2012-13)
IBBiology(2016)
Standards
HS.LS3.B,HS.LS4.B,HS.LS4.C,SP7-EngaginginArgumentfromEvidence
CCSS.ELA-Literacy.RST.9-12.7,CCSS.ELA-Literacy.WHST.9-12.1,
CCSS.Math.Practice.MP2
1.A.1,1.A.2,1.C.3,3.C.1,SP2,SP3,SP5,SP6
5.1,5.2,10.3
KEYTERMS
Enzyme,phenotype,allele,population
TIMEREQUIREMENT
Thislessonisdesignedfortwo50-minuteclassperiodsifstudentsworkingroupsoftwoorthreeandviewthe
film(15minutes)inclass.Additionaltimeforthefinalanalysisquestionsmightberequiredforhomework
dependingonstudents’pace.
SUGGESTEDAUDIENCE
Thisactivityisintendedforafirst-yearhighschoolbiologycourse(honorsorregular).Duetothefocuson
experimentaldesignanddataanalyses,thisactivitymayalsobeappropriateforAP/IBBiologyandhighschool
geographycourses.
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
PRIORKNOWLEDGE
Itwouldbehelpfulforstudentstobefamiliarwiththeterms“allele”and“phenotype”andhowtoapplythem
tospecificexamples.Inaddition,studentsshouldbeabletocalculatefrequenciesandconstructpiecharts.
Studentsalsoneedsomebasicunderstandingofevolutionbynaturalselection.
MATERIALS
Eachgroupofstudentsshouldhavethefollowing:
• GeneticDataTable(studenthandout,page8)
• PhenotypeDataTable(studenthandout,page9)
• PieChartStencils(studenthandout,page10),
prefilledpiecharts(supplementaryPDF- at the
end of this document),orcircle stickers(referto
“Procedure”belowformore information)
• WorldMap(supplementalhandout)
•
•
•
•
•
•
Calculator(oneperstudent)
Twocoloredpencils
Scissors
Gluestickortape
Computer/referencesforgeographyresearch
QuickGuide:MeasuringanIndividual’sAbilityto
DigestLactose(optional)
PROCEDURE
BeginbyhavingstudentsviewthefilmGotLactase?TheCo-evolutionofGenesandCulture.Ifyoudothisinclass,
youcanpausethemovieandreviewthedistributionsandfrequenciesofpeoplewhoarelactoseintolerant
(lactasenonpersistent)andlactosetolerant(lactasepersistent)invariouspopulationsaroundtheworld
(betweentimestamps4:15and4:35).
• InPart1,studentscalculate30geneticandphenotypicfrequencies.Dividethecalculationsupamong
students.Individualsorgroupscanthenreportbacktothewholeclass.
• InPart2,studentsmapgeneticfrequenciesbycreating30piecharts.Studentsplacethesmallpiechartson
aworldmap.Youcaneitherusetheprovidedmaporanylargeclassroomwallmapavailabletoyou.
o
Option1:Ifyouplantoletstudentscolorall30piecharts,havethemworkingroupsofthreeto
calculatethepercentagesandfillinthepiecharts.
Toavoidcuttingoutthe30PieChartStencils(page10,studenthandout),considerusingsheetsofcircle
stickers.Eachgroupofstudentscouldusetheseastheir30piechartsbysimplyoverlayingonecolor
overanother(withtheappropriatepercentage“slice”cutaway)andstickthemtotheworldmap.
Studentsshouldbeverycarefulwhenplacingthestickersonthemaptoensurethattheyarecorrectly
placed.
o
Option2:Tosavetime,usetheprefilledpiecharts,foundonthesupplementarysheettitled“PieChart.”
Thissetofpiechartsrequiresthestudenttocoloronlyfive(A,O,S,W,andCC)ofthe30piecharts
whiletherestarecompletedforthem.ReviseinstructionsforProcedurePart2onthestudenthandout
toreflectthechanges.
o
Option3:Makethisaclassproject.Todothis,projectthemaponawhiteboardandtheneachgroupof
studentsisresponsibleforfillinginthreeorfourpiecharts.Studentscanplacetheirstickersonthe
whiteboardordrawthepiechartsinbyhand.
o
Option4:DownloadtheExcelspreadsheetandhavethestudentsinputtheappropriateformulain
columnHtocalculatethefrequencies.StudentscanalsomakepiechartswithinExcel.
o
Ifyoudecidetoprintthesupplementalworldmap,setthepapersizeto11×17inches“tabloid”(under
pagesetup).Ifyoudon’thave11×17paper,youmayprintthemaponfoursheets8.5×11inchpaper
byselecting“poster.”
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
• Youmaywishtodiscusswithyourstudentsthebenefitsandlimitationsofcombiningandcomparingdata
frommultiplebutsimilarstudies.Youmayusethefollowingpromptstostartadiscussion:
o
Havestudentslookatthephenotypeandgeneticdatatables,payingparticularattentiontothe
references.Studentsshoulddescribewhattheyseeandwhytherearesomanydifferentreferences.
Pointouttostudentsthattheoriginalpurposeofthedatasetwastoseetheworldwidedistributionof
lactasepersistence.Theoriginalstudycompileddatasetsfrom100differentpublishedsourcesand
includeddatafromover200groupsofpeople.
o
Havestudentsdiscusswhythescientistsdecidedtoanalyzedatapublishedinpastscientificpapers
insteadofdoingthemeasurementsthemselves.
o
Youmaywishtomapthephenotypedataandmakestatementsaboutgeneralpatternsandtrends
betweenthegeneticandphenotypedata.Studentswillseethatwhenthepopulationshowsahigh
phenotypicfrequencyoflactasepersistence,theywilltypicallyalsoseehighfrequenciesoflactasepersistencealleles.
o
Youmaywishtodiscusssomeofthelimitationstothisdataset.Havestudentslookatgeneticand
phenotypedataofonepopulation(forexample,Hungary,X)andthecorrespondingreferences.Discuss
thelimitationsofcomparingthedataforonepopulationfromtwodifferentpapers.Remindstudents
thatwhencombiningstudies,itisveryimportanttoreadthematerialsandmethodssectionofthe
reference,acommonfeatureofstudentlabreports.Theresearchersmayhavemeasuredthesametrait
indifferentways,whichcouldaffecttheresults.Forexample,the“QuickGuide:Measuringan
Individual’sAbilitytoDigestLactose”discussestwodifferentwaystomeasurelactoseintolerance.
• StudentsmayalsoaskwhythemapdoesnotincludeNorthandSouthAmerica.Fewstudieswereconducted
ontheAmericancontinent,largelybecausemostpeoplearenotindigenoustothecontinentbutimmigrated
thererelativelyrecently.Theirlactase-persistencegenotypeswouldvarydependingontheirancestry.
• Aftercompletingthisactivity,werecommendyourstudentsdothehands-onlabentitled“Milk—HowSweet
IsIt?”(http://www.hhmi.org/biointeractive/milk-how-sweet-it),inwhichstudentsmeasureglucoselevelsin
samplesofmilkafteraddinglactase.
• IfyouwanttoknowmoreaboutDr.SarahTishkoff’sresearch,watchthe2011HolidayLecture“Geneticsof
HumanOriginsandAdaptation”athttp://media.hhmi.org/hl/11Lect2.html.
• Tolearnmoreabouthowexpressionofthelactasegeneisregulated,proceedthroughtheClickandLearn
“RegulationoftheLactaseGene”at
http://www.hhmi.org/biointeractive/evolution/Lactase_Regulation/01.html.
EXTENSIONQUESTIONS
Clinesarenottypicallyintroducedinhighschoolbiologyclassrooms,butifyouwishtoincludethatconcept,ask
studentsthefollowingquestionstopromptdiscussion:
• Inbiology,aclineisthegradualchangeinatraitorchangesinallelefrequencieswithinthegenepoolovera
geographicareawithinaspecies.Usingyourworldmapofpiecharts,lookatthelactasenonpersistence
distributionfromEnglandtoFrance,Italy,Greece,andfinallyTurkey.Doyouobserveageneralgeneticcline?
Supportyouranswerwithevidencefromthegenotype-frequencydata.
Yes,thereisageneralclinefromEnglandsoutheasttoTurkey.AsyoumovefromEnglandinthe
northwesttoTurkeyinthesoutheast,thegeneticfrequencyoflactasepersistencedecreases.For
example,England(S)94%%àFrance-(V)68%àGreece(W)-17%àTurkey-(BB)6%.
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
• Attimes,clinesaredefinedbyenvironmentalchangeswithinthestudyarea.Basedonyouranswerto
question5,developanexperimentalquestionthatyouwouldliketotestregardinglinksbetween
environment,culture,andlactasepersistenceinthepopulationsincludedinquestion5.
Answersmayvary.Oneexample:ArethepeopleinEnglandmoredependentonmilkproductsand
domesticationoflivestockthanthepeopleinsouthernEuropeduetotheshortergrowingseasoninthe
northeast?
ANSWERKEY
ProcedurePart1:AnalyzingtheDataTables
Seepages9and10ofthisdocumentforthecalculatedgeneticandphenotypefrequencies.
QuestionsPart1:DataAnalysis
6. LookattheSomalipopulationinEthiopia(A)inthegeneticdataset(page9).
a. Howmanypeopleweretestedinthestudy?74people b. Howmanypeoplehaveatleastonealleleassociatedwiththelactase-persistencetrait?22people
c. Howmanypeopledidnothaveallelesassociatedwiththelactase-persistencetrait?(74–22)=52
people
d. CalculatethefrequencyofpeopleintheSomalistudywhodidnothaveoneofthefouralleles
associatedwiththelactase-persistencetrait.52/74=0.70
e. AssumethatthecalculatedfrequencywasanaccuraterepresentationoftheentireSomalipopulation.
ThepopulationofSomaliaisaround10million.Howmanypeopleintotalwouldyouexpecttohaveat
leastonealleleassociatedwiththelactase-persistencetrait?10,000,000×0.30=3,000,000people
wouldbeexpectedtohaveatleastonecopyofalactase-persistenceallele.
7. Usingthephenotypedatatable,lookattheSomalipopulation(A)inEthiopia.
a. Howmanypeopleweretestedinthephenotypestudy?90people
b. Howmanypeopletestedpositivefortheabilitytodigestlactose?22people
c. Howmanypeoplewereunabletodigestlactose?68people
d. CalculatethefrequencyofpeopleintheSomalistudywhotestednegativeforthelactase-persistence
phenotype.(68/90)=0.76
e. Whatdidthescientistsmeasuretocollectthegeneticandphenotypedata?Inotherwords,inwhatway
dothetwodatasetsdiffer?Thelactase-persistencefrequencyonthegeneticdatatableisbasedon
measuringthefrequenciesofpeopleineachpopulationwhohaveoneormoreofthefouralleles
associatedwiththelactase-persistencetrait.Thephenotypedatawasbasedonmeasuringthe
frequenciesofpeopleineachpopulationwhoshowedalactase-persistencetraitinoneoftwotests,
thebloodglucosetestorthehydrogenbreathtest.
8. Fromthedatatables,recordthelactase-persistence(LP)frequenciesandreferencesforthefollowing
population:
POPULATION
Hungary
(Hungarians)(X)
DATATYPE
Geneticdata
Phenotypedata
LPFREQUENCY
0.86
0.63
REFERENCES
Nagyetal.(2009),Eur.J.Clin.Nutr.63,909.
Czeizeletal.(1983),Hum.Genet.64,398.
a. Writedowntwodifferencesyounoticeaboutthedata.
Possibleanswersincludethefollowing:
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
Thegeneticandphenotypefrequenciesdonotmatch.
Thegeneticandphenotypedatacamefromtwodifferentstudies.
Thestudiesweredonebydifferentauthorsandindifferentyears.
b. Providetworeasonswhythefrequencyoflactasepersistencemightbedifferentwhencomparing
geneticandphenotypedataintheHungarianpopulation(X).(Hint:Thinkofboththemethodsusedto
determinethesefrequenciesandthebiologicaldifferencesbetweengenotypeandphenotype
frequencies.)
Answersmayvary.Twocommonresponses:1)Thedataarefromtwodifferentstudies;therefore,the
peoplesampledforonestudymaynotnecessarilybethesameasthepeoplesampledforthesecond.
2)Thepeoplewhoaregenotypicallylactasepersistentmaybelactoseintolerantforotherreasons.
9.
Inageneticstudy,1876individualsweresampledinFinland,whereas58peopleweresampledinFrance.
(Finland’stotalpopulationin2008was5.3million,whileFrance’spopulationin2004was60.4million.)
a. Whichdatasetprobablyrepresentsthecountrymoreaccurately?
b. Whattwoquestionswouldyoulikeansweredaboutthesamplestohelpyoufeelcomfortablethatthey
accuratelyrepresentthepopulationofaparticularcountry?
TheFinnishstudymoreaccuratelyrepresentsthecountrybecausethesamplesize(1,876)islarger
andbecausealargerpercentageofthetotalpopulationwassampled(1,876of5.3million)compared
totheFrenchstudy(58of60.4million).Questionsforresearchersmightincludewhetherthey
sampledpeoplewhosefamilyhadalonghistoryoflivinginFranceandiftheytriedtosamplepeople
fromdifferentregionsinFrance.
10. Comparingthegeneticdatatothephenotypedata,identifyapatternyouobserveinthetwodatasetsin
thethreepopulationsfromSudan(F,G,H).
Eitherofthesetwoanswersisacceptable:1)Thelactase-persistenceallelefrequenciesarealllowerthan
thelactase-persistencephenotypefrequencies.2)Thegeneticfrequenciesarepositivelycorrelatedwith
phenotypefrequencies.Forexample,whenthegeneticfrequencyforlactasepersistenceishigh,the
phenotypefrequencyisalsohigh.
11. Usingthegeneticinformationprovided,whatdothelactase-persistencefrequenciesfromthepopulations
fromSenegal(Wolof-D),Sudan(Dinka-G),andJapan(Japanese-N)haveincommon?
Thegeneticfrequenciesforlactasepersistenceareallzero.
12. Thelactase-persistencephenotypefrequencydatafromthesethreepopulationsrangefrom25%to51%.
Basedonyourknowledgeofmoleculargenetics(DNA,genes,geneexpression),whatmightbeareasonfor
thisdifference?
Answersmayvary.ThegeneticstudieswerebasedonDNAsequencingprotocolslookingforoneoffour
identifiedallelesassociatedwithlactasepersistence.Anunknownalleleordifferentgenemaybe
associatedwithlactasepersistence.
13. Basedongeneticandphenotypedata,developahypothesisabouttheculturalpracticesregarding
domesticatinglivestockandconsumingmilkofthepopulationssampledinUganda(I),China(P),andPapua
NewGuinea(R).
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
Sincethegeneticdataandphenotypelactase-persistencefrequenciesmeasuredinthesethree
populationsarelow(all<0.10),theancestorsofthesepeoplemostlikelydidnotdomesticatelivestockor
consumemilkproducts.Becausetheseculturesdidnotcreateanenvironmentinwhichmilkwasavailable
foradults,therewasnoopportunityfornaturalselectiontoactonthelactase-persistencetrait.Asa
result,thelactase-persistencefrequenciesremainedlowinthesepopulations.
14. TheDinkapeopleofSudan(G)areknownasagropastoralists.Theydependonagricultureduringtherainy
seasonandlivestockherdinganddomesticationduringthedryseason.Accordingtothestudy,theDinka
peoplesampledhada0%frequencyoflactasepersistencewhenlookingatthegeneticdata,whichisnot
consistentwiththeiragropastoralistculture.Whatmaybealimitationtothisparticularresearchstudy?
Oneexampleofanansweristhatthenumberofpeoplesampled(18)inthispopulationislowto
accuratelyrepresenttheDinkapeopleasawhole.Studentsmayalsocomeupwithotherreasons.
ProcedurePart2:MappingtheAlleleFrequencies
Forapictureofthecorrectplacementofpiechartsontheworldmap,seepage11.
NOTE:Studentsshouldbeawarethatthelactase-persistencefrequenciesbasedonthegeneticdatarepresent
thepeoplewhohaveoneoftheallelesthatscientistshaveidentifiedtobeassociatedwithlactasepersistence.
Thisnumbermaynotrepresenteveryonewhoislactasepersistent,becauseothermutations,notidentifiedor
measuredinthestudy,maybeassociatedwiththelactase-persistencetrait.
Similarly,forthephenotypedata,thelactase-persistencetestisnotalways100%accurate.Forexample,one
waytotestforlactasepersistenceistomeasureanincreaseinglucoseafterdrinkingmilk.Insomecases,other
factorscouldcontributetoaglucosespike.Theinabilitytotoleratelactose(ormilkproducts)canbedueto
causesotherthanlactasenonpersistence,sonoteveryonewhoislactasepersistentcantoleratemilkproducts.
QUESTIONSPART2:MAPANALYSIS
20. Lookingattheglobaldistributionofpiechartsonyourmap,writethreeclaimsthatyoucouldmakeabout
theworldwidedistributionoflactasepersistence.Notetheevidencethatsupportsyourclaimand
alternativeexplanationsordatathatdonotsupportyourclaim.(Forexample,inEurope,youcouldmakea
claimabouthowthepatternoflactasepersistence/nonpersistencefrequenciesrelatestolatitude.)
Answerswillvary.Belowareafewexamples:
• Ingeneral,thefrequencyoflactasepersistenceishigherinEuropethaninotherareasrepresentedon
themap.EvidencenotsupportingthisclaimcomesfrompopulationsfromSardinia(Z)andGreece(W).
• MostofthepopulationsinAsiatendtowardlactasenonpersistence,exceptfortheBedouinpopulation
(CC)andtheArabpopulation(DD)inSaudiArabiaandtheUdmurts(O)inRussia.
• MostoftheAfricanpopulationsarelactasenonpersistent,exceptfortheMaasaiinKenya(B)and
Tanzania(K)andtheBurungeinTanzania(J).
• Ingeneral,therearemorepopulationsinwhichthemajorityofpeoplearelactasenonpersistent.
21. Whatdoyounoticeaboutthelactase-persistencefrequenciesoftheMaasaipeopleinKenya(B)andthe
Sengwerpeople,alsoinKenya(C)?
ThefrequencyoflactasepersistenceishighintheMaasaipeopleandverylowintheSengwerpeople.
a. Basedontheinformationpresentedinthefilm,whatcouldhaveaccountedforthisdifference?Explain
youranswer.
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
TheMaasaipeoplearepastoralistsandhavebeendomesticatinglivestockforthousandsofyears.The
highfrequencycouldthereforebeattributedtotheselectiveadvantageassociatedwithbeingableto
digestlactose.
22. LookatthegeneticdataforthetwopopulationsfromEngland(S,T)andthetwopopulationsfromItaly(Y,
Z).WhatdoyounoticewhenyoucompareStoTandYtoZwithineachcountry?Whatquestionor
questionsdoesthiscomparisonraiseforyou?
ThetwopopulationsfromEngland(S,T)havesimilarlactase-persistencefrequencies,whilethetwo
populationsfromItaly(Y,Z)varysignificantlyinthefrequencydistributions.TheSardiniandatashowa
frequencyof0.14,whilethedatafromnorthernItalyshowa0.59frequency.
23. WhatdoyounoticewhenanalyzingthegeneticdataforNorthernEuropeandthoseforEast
Asia/Australasia?Whatreasoncouldtherebeforthedifferenceyouobserve?
ThedatafromNorthernEuropeshowahighlactase-persistencefrequency,whilethedatafrom
Asia/Australasiashowamuchlowerlactase-persistencefrequency.Thedifferencesbetweenthesetwo
globalregionscouldbeattributedtotheirculturalpractices.ComparedtotheEastAsian/Australasian
people,NorthernEuropeansmaybemoredependentondomesticatedlivestockandmilkconsumption.
24. FindtheallelefrequencypiechartinChinafortheHanpeople(P).TheHanpeoplemakeup92%of
mainlandChina’spopulationandroughlyone-fifthoftheworld’spopulation.Ofthe200peoplesampled,
whatpercentagewaspredictedtobelactoseintolerant?100%lactoseintolerantorlactasenonpersistent.
Astudypublishedin2009showsanincreaseinmilkconsumptionamongtheChinesepeople.Seethegraph:
NOTE:Forcomparison,theaveragetotal
Percapitaconsumptionof
numberofpoundsofdairyproductsavailable
dairyproductsinruraland
toeatordrinkannuallyintheUSwas275.9
urbanhouseholds
pounds(125kg)in2012.
Source:Chinesestatisticalyearbook
25. Fromthegraphabove,predicthowthegeneticdataforlactase-persistencefrequencymightchangeifthe
samepopulationissampledagainin1000years.Explainyourprediction,notingwhat(ifany)selective
pressureswouldbepresent.
Answersmayvary.Ifmilkconsumptionremainshigh,andifthosewhodon’tdrinkmilkareata
reproductivedisadvantage,thefrequencyoflactasepersistenceintheHanpopulationwilllikelyincrease
overthenext1000years.Thisisduetotheselectiveadvantageofdigestinglactose,whichhasbecome
moreprevalentintheculturaldiet.However,todaypeoplehavemanydifferentfoodsanddrinks
availabletothem,sotheselectivepressureshavechangedoverthepast10,000years.
NOTE:Studentsshouldbeawarethattheremustbeselectivepressuresthataffectthereproductive
successandsurvivaloftheindividualsforgeneallelefrequenciestochangeinapopulationasa
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Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
consequenceofselection.Ifmoderninterventionsormedicines,likeLactaid,enablelactase-nonpersistent
individualstosurviveandreproduce,nochangeswillbeobservedinlactase-persistencegenotype
frequenciesduetonaturalselection.
26. ThemainfoodsourcesoftheBantupeopleofUganda(I)arematoke(afruitinthebananafamily),eggs,fish,
beans,nuts,beef,chicken,goats,andvariousfruitsandvegetables.Explainhowthedatapresentedinthis
activityeithersupportordonotsupportwhatyounowknowabouttheirculturaldiet.
ThefrequencyoflactasepersistenceamongtheBantupopulationsampledisextremelylow(allele
frequency=0%,phenotype=6%).Thesedatasupportwhatisknownabouttheculturaldietofthese
people.Bantuarenotdependentonmilkproducts;theydependmoreonvegetables,fruit,nuts,and
meat.Thissuggeststhatlactasepersistenceoffersnoselectiveadvantageorthatthegeneticvariation
wasnotpresentinthispopulationhistoricallyforlactasepersistencetoevolve.
27. Inafewsentences,supporttheclaimthatlactasepersistenceisagoodexampleofgene/culturecoevolution.Yourexplanationshouldincludeseveralpiecesofevidence.
Answerswillvary.Humans,likeallspecies,evolveandadapttotheenvironmentthroughnatural
selection.Lactasepersistenceisanexampleofahumanadaptationthatarosewithinthelast9,000years
inresponsetoaculturalchange.Thepracticeofdairyingmademilkfromdomesticatedanimalsavailable
foradultstodrink,providinganenvironmentinwhichlactasepersistencebecameadvantageous.The
cultureofdairyingcreatedastrongselectiveadvantage,becauseonlythepeoplewiththeabilitytodigest
milkcouldbenefitfromitnutritionally.
Forexample,takethetwopopulationsinKenya,theMaasaiandtheSengwer,whichvaryintheircultural
practices:TheMaasaidomesticatetheirlivestockandshowahighfrequencyoflactasepersistence,while
theSengwerdonotdependonmilkandhaveaverylowfrequencyoflactasepersistence.
AUTHOR
WrittenbyAnnBrokaw,RockyRiverHighSchool
EditedbySusanDodge,LauraBonetta,PhD,HHMI,andMelissaCsikari,HHMI
ReviewedbyPaulBeardsley,PhD,CalPolyPonoma
CopyeditedbyLindaFelaco
FIELDTESTERS
AmandaCrisostomo,ScienceandMathInstitute;DanaFrank,CommunityHouseMiddleSchool;HelenSnodgrass,YESPrepNorthForest;
IngridWoods,SemiahmooSecondarySchool;JenStites,JohnHancockCollegePrepHighSchool;JeremyBarlow,UniondaleHighSchool;
KimHayen,HeritageHighSchool;MelissaCsikari,ColonialForgeHighSchool
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PublishedApril2017
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www.BioInteractive.org
Africa
C
Africa
Africa
H
I
J
Asia
Asia
O
P
Q
Finland
Europe
Europe
Europe
Europe
U
V
W
X
Turkey
SaudiArabia
Europe
Near/MiddleEast
Near/MiddleEast
Near/MiddleEast
Near/MiddleEast
Z
AA
BB
CC
DD
PublishedMarch2017
Page9of11
248
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153
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947
1168
34
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0.61
0.86
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0.91
0.94
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#Peoplewitha
Lactase#People
lactasepersistence
sampled(n) persistenceallele frequency
Source:GlobalLactasePersistenceAssociationDatabase,http://www.ucl.ac.uk/mace-lab/resources/glad
Arab
Bedouin
AnatolianTurk
Jordanian
Sardinian
NorthernItalian
Hungarian
Greek
French
Finn
English,southeastern
English,northern
Han
Mongol
Papuan
Udmurt
Japanese
Indian
Tadjik
Maasai
Burunge
Bantu
Jaali
Dinka
BeniAmer
Xhosa
Wolof
Sengwer
Maasai
Somali
Population
Enattahetal.(2008)Am.J.Hum.Genet.82,57.
Ingrametal.(2009)Hum.Gen.124,579
Mulcare(2006)London:UniversityofLondonPhD.
Enattahetal.(2008)Am.J.Hum.Genet.82,57.
Anagnostouetal.(2009)Am.J.Hum.Biol.21,217.
Bersaglierietal.(2004)Am.J.Hum.Genet.74,1111.
Nagyetal.(2009)Eur.J.Clin.Nutr.63,909.
Anagnostouetal.(2009)Am.J.Hum.Biol.21,217.
Bersaglierietal.(2004)Am.J.Hum.Genet.74,1111.
Enattahetal.(2008)Am.J.Hum.Genet.82,57.
DaveySmithetal.(2009)Eur.J.HumanGen.,17,357-367.
DaveySmithetal.(2009)Eur.J.HumanGen.,17,357-367.
Bersaglierietal.(2004)Am.J.Hum.Genet.74,1111.
Sunetal.(2007)AsiaPac.J.Clin.Nutr.16,4.
Enattahetal.(2008)Am.J.Hum.Genet.82,57.
Enattahetal.(2008)Am.J.Hum.Genet.82,57.
Bersaglierietal.(2004)Am.J.Hum.Genet.74,1111.
Mulcare(2006)London:UniversityofLondonPhD.
Mulcare(2006)London:UniversityofLondonPhD.
Tishkoffetal.(2007)Nat.Genet.39,31.
Tishkoffetal.(2007)Nat.Genet.39,31.
Mulcareetal.(2004)Am.J.Hum.Genet.74,1102.
Ingrametal.(2009)Hum.Gen.124,579.
Tishkoffetal.(2007)Nat.Genet.39,31.
Ingrametal.(2009)Hum.Gen.124,579.
Torniainenetal.(2009)BMCGenet.10,31.
Ingrametal.(2009)Hum.Gen.124,579.
Tishkoffetal.(2007)Nat.Genet.39,31.
Tishkoffetal.(2007)Nat.Genet.39,31.
Ingrametal.(2009)Hum.Gen.124,579.
Reference
Educator Materials
SaudiArabia
Jordan
Italy
Europe
Y
Italy
Hungary
Greece
France
England
Europe
T
England
Europe
PapuaNewGuinea
China
China
S
Australasia
Asia
N
R
Asia
Russia
India
Japan
Asia
M
Afghanistan
Asia
Tanzania
Tanzania
Uganda
L
Africa
Africa
G
K
Sudan
Africa
Sudan
Sudan
Africa
F
SouthAfrica
Senegal
Kenya
Kenya
Ethiopia
Africa
Africa
B
Africa
Africa
A
Country
E
D
Continent/
Region
Dataindicatewhetherapersoninthesamplehasatleastonecopyofthelactasepersistenceallele.
GeneticData
Activity
TheMakingoftheFittest:
Got Lactase? The Co-evolution of Genes and Culture
NaturalSelectionandAdaptation
Africa
Africa
Africa
Africa
Africa
Africa
Africa
Africa
Africa
Asia
Asia
Asia
Asia
Asia
Asia
Australasia
Europe
Europe
Europe
Europe
Europe
Europe
Europe
Near/Middl
eEast
Near/Middl
eEast
Near/Middl
eEast
Near/Middl
eEast
B
C
D
www.BioInteractive.org
E
F
G
H
I
J
K
L
M
N
O
P
Q
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S
U
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Y
Z
PublishedApril2017
Page10of11
Arabs
Bedouin
SaudiArabia
AnatolianTurks
Turkey
SaudiArabia
Jordanian
Sardinian
NorthernItalian
Hungarian
Greek
French
Finns
British
Papuan
Mongol
Han
Udmurts
Japanese
Indian
Tadjik
Maasai
Burunge
Bantu
Jaali
Dinka
BeniAmer
Xhosa
Wolof
Sengwer
Maasai
109
21
122
148
53
208
535
600
102
638
150
30
198
248
30
40
100
79
15
16
17
113
208
40
17
53
12
26
90
47
17
32
37
6
102
337
330
78
530
143
3
24
20
18
11
36
14
10
6
1
60
52
35
3
27
2
23
22
0.43
0.81
0.26
0.25
0.11
0.49
0.63
0.55
0.76
0.83
0.95
0.10
0.12
0.08
0.60
0.28
0.36
0.18
0.67
0.38
0.06
0.53
0.25
0.88
0.18
0.51
0.17
0.88
0.24
Lactasepersistence
frequency
Source:GlobalLactasePersistenceAssociationDatabase,http://www.ucl.ac.uk/mace-lab/resources/glad
DD
CC
BB
Jordan
Italy
Italy
Hungary
Greece
France
Finland
China
PapuaNew
Guinea
England
China
Russia
Japan
India
Tanzania
Uganda
Sudan
Sudan
Sudan
SouthAfrica
Senegal
Kenya
Kenya
Somali
Population
Numberofpeople
People
whotested
sampled(N) positiveforlactase
persistence
Dissanayakeetal.(1990)Ann.SaudiMed.10,598.
Dissanayakeetal.(1990)Ann.SaudiMed.10,598.
Flatzetal.(1986)Am.J.Hum.Genet.38,515.
Hijazietal.(1983)Trop.Geogr.Med.35,157.
Melonietal.(1998)Ital.J.Gastroenterol.Hepatol.30,490.
Burgioetal.(1984)Am.J.Clin.Nutr.39,100.
Czeizeletal.(1983)Hum.Genet.64,398.
Kanaghinisetal.(1974)Am.J.Dig.Dis.19,1021.
Cloarecetal.(1991)Gastroenterol.Clin.Biol.15,588.
Jussila(1969)Ann.Clin.Res.1,199.
Fergusonetal.(1984)Gut25,163.
Jenkinsetal.(1981)Ann.Hum.Biol.8,447.
Yongfaetal.(1984)Hum.Genet.67,103.
Yongfaetal.(1984)Hum.Genet.67,103.
Kozlov(1998)Int.J.CircumpolarHealth57,18.
Yoshidaetal.(1975)Gastroenterol.Jpn.10,29.
Desaietal.(1970)IndianJ.Med.Sci.24,729.
Rahimietal.(1976)Hum.Genet.34,57.
Tishkoffetal.(2007)Nat.Genet.39,31.
Tishkoffetal.(2007)Nat.Genet.39,31.
Cooketal.(1966)Lancet1,725.
Bayoumietal.(1981)Hum.Genet.57,279.
Bayoumietal.(1982)Am.J.Phys.Anthropol.58,173.
Bayoumietal.(1982)Am.J.Phys.Anthropol.58,173.
Segaletal.(1983)Am.J.Clin.Nutr.38,901.
Arnoldetal.(1980)C.R.SeancesSoc.Biol.Fil.174,983.
Tishkoffetal.(2007)Nat.Genet.39,31.
Tishkoffetal.(2007)Nat.Genet.39,31.
Ingrametal.(2009)Hum.Gen.124,579.
Reference
Got Lactase? The Co-evolution of Genes and Culture
AA
Tanzania
Afghanistan
Africa
A
Ethiopia
Africa
Country
Continent/
Region
PhenotypeData
Activity
Educator Materials
Activity
Got Lactase? The Co-evolution of Genes and Culture
Educator Materials
Title:Worldwidedistributionoflactasepersistenceandlactasenonpersistencealleles
OldWorldMap–AnswerKey
www.BioInteractive.org
PublishedApril2017
Page11of11
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