LAB:MODELINGCOLORBLINDNESS
NAME: PERIOD:
DATE:
Objective:
Icanmodelhowcolorblindnessispassedfromparentstooffspring.
IcanusePunnettsquarestopredictthegenotypesandphenotypesofoffspring.
Icanusethedatafrommymodeltoexplainwhycolorblindnessismuchmorecommoninmenthaninwomen.
Materials:
TwoSmallCups
5WhiteBeans+1Red/BrownBean
Procedure:
1) Setup–
a. Youwilluse1dixiecuptorepresenteachparent.(ThismeansIwillneed_________cups.Ishouldlabelone
ofthem_____________________________andtheother_______________________________.)
b. ThewhitebeansrepresentXchromosomes.ThebrownbeanrepresentstheYchromosome.Useamarkerto
put“b”on2ofyourwhitebeans.Thisrepresentstherecessivegeneforcolorblindness.Puta“B”onthe
other3whitebeans.Thisrepresentsthedominantgenefornormalcolorvision.
2) Thislabinvolvesseveraldifferentinvestigations.Foreachinvestigationdescribedbelow,determinewhich2beans
shouldgointothe“mother”cupandwhich2beansshouldgointothe“father”cup.
3) Then,closeyoureyesandpickonebeanfromeachcup.Thebeanpickedfromthe“mother”cuprepresentswhichsex
chromosomethemotherwillpassontothechild.Thebeanpickedfromthe“father”cuprepresentswhichsex
chromosomesthefatherwillpassontothechild.
4) Recordthedescriptionofthebeans(forexample,“whitebean,B,”“brownbean,”etc.)inyourdatatable.Then,put
eachbeanbackinthecupitcamefrom.
5) Fillintheremainingcolumnsinyourdatatablebasedonthebeansyoudrew.
6) Repeateachinvestigationuntilyouhaveperformedatotalof10trials.Eachtrialrepresents1childfromthose
parents.
7) Whenyouhavecompletedyourinvestigation,pleaseanswertheanalysisquestions.Youmaydiscussyourideaswith
others,buteachpersonmustturninhis/herownanswers(inhis/herownwords!).Pleaseanswerquestions
thoughtfullyincompletesentences.
Investigation1:Fatherhasnormalvision(____).Motherishomozygousfornormalvision(____).
Trial BeanfromMother:
BeanfromFather:
GenotypeofChild:
Whatisthe
child’ssex?
Isthechildcolorblind,
normal,oracarrier?
(Whatcolorisit?
DoesitcarryBorb?)
(Whatcolorisit?
DoesitcarryBorb?)
(XBXB,XBY,XbXB,XbXb,
XbY)
1
2
3
4
5
6
7
8
9
10
(Male/Female)
Investigation2:Fatheriscolorblind(_____).Motherishomozygousfornormalvision(______).
Trial BeanfromMother:
BeanfromFather:
GenotypeofChild:
Whatisthe
child’ssex?
Isthechildcolorblind,
normal,oracarrier?
(Whatcolorisit?
DoesitcarryBorb?)
(Whatcolorisit?
DoesitcarryBorb?)
(XBXB,XBY,XbXB,XbXb,
XbY)
1
2
3
4
5
6
7
8
9
10
(Male/Female)
Investigation3:Fatherhasnormalvision(_____).Motherisacarrierforcolorblindness(_____).
Trial BeanfromMother:
BeanfromFather:
GenotypeofChild:
Whatisthe
child’ssex?
Isthechildcolorblind,
normal,oracarrier?
(Whatcolorisit?
DoesitcarryBorb?)
(Whatcolorisit?
DoesitcarryBorb?)
(XBXB,XBY,XbXB,XbXb,
XbY)
1
2
3
4
5
6
7
8
9
10
(Male/Female)
Investigation4:Fatherhasnormalvision(________).Motheriscolorblind(________).
Trial BeanfromMother:
BeanfromFather:
GenotypeofChild:
Whatisthe
child’ssex?
Isthechildcolorblind,
normal,oracarrier?
(Whatcolorisit?
DoesitcarryBorb?)
(Whatcolorisit?
DoesitcarryBorb?)
(XBXB,XBY,XbXB,XbXb,
XbY)
1
2
3
4
5
6
7
8
9
10
(Male/Female)
Analysis:
1) InInvestigation1:
Whatwasthemother’sgenotype?_________Wasshenormal,acarrier,orcolorblind?__________________
Whatwasthefather’sgenotype?_________Washenormal,acarrier,orcolorblind?__________________
Howmanynormalvisionsonsdidyoufind?
_____________
Howmanynormalvisiondaughtersdidyoufind?
_____________
Howmanycolorblindsonsdidyoufind?
_____________
Howmanycolorblinddaughtersdidyoufind? _____________
Howmanycarriersonsdidyoufind?
_____________
_____________
Howmanycarrierdaughtersdidyoufind?
Whatconclusionscanyoudrawfromyourdataaboutthechildrenyouwouldexpectfromtheseparents?
Whenwehavea_______________________motheranda______________________father,wewouldexpect
__________________________________________________________________________________________
__________________________________________________________________________________________
PleasecreateaPunnettsquarethatshowsthepossiblechildrenfromthissamemotherandfather.(Hint:Put
themother’sgenotypeacrossonesideandthefather’sgenotypeacrosstheother.)
WhatdoesthePunnettsquarepredictaboutthechildrenthatyouwouldexpectfromtheseparents(include
percentages)?Isthisconsistentwithyourdata?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
2) InInvestigation2:
Whatwasthemother’sgenotype?_________Wasshenormal,acarrier,orcolorblind?__________________
Whatwasthefather’sgenotype?_________Washenormal,acarrier,orcolorblind?__________________
Howmanynormalvisionsonsdidyoufind?
_____________
Howmanynormalvisiondaughtersdidyoufind?
_____________
Howmanycolorblindsonsdidyoufind?
_____________
Howmanycolorblinddaughtersdidyoufind? _____________
Howmanycarriersonsdidyoufind?
_____________
_____________
Howmanycarrierdaughtersdidyoufind?
Whatconclusionscanyoudrawfromyourdataaboutthechildrenyouwouldexpectfromtheseparents?
Whenwehavea_______________________motheranda______________________father,wewouldexpect
__________________________________________________________________________________________
__________________________________________________________________________________________
PleasecreateaPunnettsquarethatshowsthepossiblechildrenfromthissamemotherandfather.(Hint:Put
themother’sgenotypeacrossonesideandthefather’sgenotypeacrosstheother.)
WhatdoesthePunnettsquarepredictaboutthechildrenthatyouwouldexpectfromtheseparents(include
percentages)?Isthisconsistentwithyourdata?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
3) InInvestigation3:
Whatwasthemother’sgenotype?_________Wasshenormal,acarrier,orcolorblind?__________________
Whatwasthefather’sgenotype?_________Washenormal,acarrier,orcolorblind?__________________
Howmanynormalvisionsonsdidyoufind?
_____________
Howmanynormalvisiondaughtersdidyoufind?
_____________
Howmanycolorblindsonsdidyoufind?
_____________
Howmanycolorblinddaughtersdidyoufind? _____________
Howmanycarriersonsdidyoufind?
_____________
_____________
Howmanycarrierdaughtersdidyoufind?
Whatconclusionscanyoudrawfromyourdataaboutthechildrenyouwouldexpectfromtheseparents?
Whenwehavea_______________________motheranda______________________father,wewouldexpect
__________________________________________________________________________________________
__________________________________________________________________________________________
PleasecreateaPunnettsquarethatshowsthepossiblechildrenfromthissamemotherandfather.(Hint:Put
themother’sgenotypeacrossonesideandthefather’sgenotypeacrosstheother.)
WhatdoesthePunnettsquarepredictaboutthechildrenthatyouwouldexpectfromtheseparents(include
percentages)?Isthisconsistentwithyourdata?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
4) InInvestigation4:
Whatwasthemother’sgenotype?_________Wasshenormal,acarrier,orcolorblind?__________________
Whatwasthefather’sgenotype?_________Washenormal,acarrier,orcolorblind?__________________
Howmanynormalvisionsonsdidyoufind?
_____________
Howmanynormalvisiondaughtersdidyoufind?
_____________
Howmanycolorblindsonsdidyoufind?
_____________
Howmanycolorblinddaughtersdidyoufind? _____________
Howmanycarriersonsdidyoufind?
_____________
_____________
Howmanycarrierdaughtersdidyoufind?
Whatconclusionscanyoudrawfromyourdataaboutthechildrenyouwouldexpectfromtheseparents?
Whenwehavea_______________________motheranda______________________father,wewouldexpect
__________________________________________________________________________________________
__________________________________________________________________________________________
PleasecreateaPunnettsquarethatshowsthepossiblechildrenfromthissamemotherandfather.(Hint:Put
themother’sgenotypeacrossonesideandthefather’sgenotypeacrosstheother.)
WhatdoesthePunnettsquarepredictaboutthechildrenthatyouwouldexpectfromtheseparents(include
percentages)?Isthisconsistentwithyourdata?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
5) Lookatall4ofyourinvestigations.
Whatisthetotalnumberofmalesyoufound? ______________
Whatisthetotalnumberoffemalesyoufound?
______________(Hint:Males+Femalesshould=40)
In40trials,howmanymaleswouldyouexpecttofind?______________
In40trials,howmanyfemaleswouldyouexpecttofind?______________
Howdohumansexchromosomes(XandYchromosomes)ensurethatanequalnumberofmalesandfemales
arebornineachgeneration?(PleasesupportyouranswerwithaPunnettsquare.)
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
6) Isitmorelikelyforafemaleormaletobecolorblind?Why?
__________________________________________________________________________________________
________________________________________________________________________________________
7)Noneofthecrossesinthislabproducedcolorblinddaughters.Whatparentalgenotypeswouldbenecessaryto
producecolorblinddaughters?PleasesupportyouranswerwithaPunnettsquare.
Mother’sGenotype:____________________________
Father’sGenotype:____________________________
8) Isitpossibleforasontobeacarrierforcolorblindness?Whyorwhynot?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________