Apple Genetics
Name _________________________
Part 1: Comparing Royal Gala and Braeburn Apples
RoyalGalaApple
BraeburnApple
Explainwhatyouobserveontheoutsideandinsideofthisparticularapple.
Writedownwhatyounotice,stemstructure,seedlayout,andcoloring.
Look
OutsideofApple
InsideofApple
Smell
OutsideofApple
InsideOfApple
Explainwhatyouobserveusingyoursenseofsmell.
Explainwhatyouobserveaboutthetextureoftheapple.i.e.skin,meat,seed,
stem
Touch
OutsideofApple
(Texture)
InsideofApple
(Numberof
seedsandseed
shape)
Taste
Tartness
Sweetness
Juiciness
Crunchiness
Explainwhatyouobservewhenyoutasteyourapple.
1
Apple Genetics
(continued)
Part 2: Analyzing the Data:
1. ExplainwhatsimilaritiesyoufoundintheRoyalGalaandBraeburnapples?
2. ExplainwhatdifferencesyoufoundinRoyalGalaandBraeburnapples?
Part 3: Completing Punnett Squares
WhenmakingobservationsinPart1,youdescribedtraitsforeachapplesuchascolor,juiciness,or
sweetness.Thesetraitsaredeterminedbythegenesintheapple.Ifweweretocrossbreed
blossomsonaRoyalGalaappletreewithpollenfromaBraeburnappletree,theresultingfruit
wouldlook,smell,taste,andfeellikeaRoyalGalaapple,buttheseedsinsidewouldpossessgenes
frombothoftheseparents.Theseedscouldbeplantedandgrownintoanewhybridwithfruitthat
hastraitsofboththeRoyalGalaandBraeburnapple.
Inthisactivity,wewillimaginethatthetraitsyouobservedaredeterminedbyMendelian
inheritanceinwhichasinglegenedeterminesatrait.Eachtraitisdominantorrecessiveandthe
allelespasseddownfromtheparentsdeterminewhetherthetraitwillbeobservedintheoffspring.
BelowareexamplesofgenotypesthattheGalaandBraeburnapplesmaypossess.NOTE:These
genotypesaretobeusedasexamplesonlyanddonotrepresentaccurategenotypes.Youwill
usethisinformationtocompletePunnettSquaresonthefollowingpageandcalculateprobabilities
foreachgenotype.
a.
b.
c.
d.
e.
f.
Tartnessisrecessive(Gala’sgenotypeisTT,Braeburn’sgenotypeistt)
Sweetnessisrecessive(Gala’sgenotypeisss,Braeburn’sgenotypeisSS)
Juicinessisdominant(Gala’sgenotypeisJJ,Braeburn’sgenotypeisJJ)
Crunchinessisdominant(Gala’sgenotypeisCc,Braeburn’sgenotypeisCC)
Redskincoloringisdominant(Gala’sgenotypeisRR,Braeburn’sgenotypeisRr)
Smoothskintextureisdominant(Gala’sgenotypeisBb,Braeburn’sgenotypeisBb)
2
Apple Genetics
(continued)
CompletethePunnettSquaresandcalculatetheprobabilityofeachgenotypeforalltraits.
Tartness:(Example)
t
T
T
Tt
Tt
Sweetness
s
S
Tt
Tt
t
SS=__________
Tt=_____100%_
Ss=__________
tt=________0%__
ss=__________
J
Crunchiness
J
J
J
Probabilityofoffspringgenotypes:
C
Cc=__________
R
r
Probabilityofoffspringgenotypes:
Probabilityofoffspringgenotypes:
Jj=__________
R
c
C
CC=__________
R
C
JJ=__________
jj=__________
RedSkinColoring
Probabilityofoffspringgenotypes:
TT=_______0%__
Juiciness
S
Probabilityofoffspringgenotypes:
s
cc=__________
SmoothSkinTexture
B
B
b
b
Probabilityofoffspringgenotypes:
RR=__________
BB=__________
Rr=__________
Bb=__________
rr=__________
bb=__________
3
Apple Genetics
(continued)
Part 4: Jazz Apple Observation:ObserveandrecordthetraitsoftheJazzapple.
JazzAppleObservations
Explainwhatyouobserveontheoutsideandinsideofthisparticularapple.
Writedowneverythingyounotice,stemstructure,seedlayout,andcoloring.
Look
OutsideofApple
InsideofApple
Smell
Explainwhatyouobserveusingyoursenseofsmell.
OutsideofApple
InsideOfApple
Explainwhatyouobserveaboutthetextureoftheapple.i.e.skin,meat,seed,
stem
Touch
OutsideofApple
InsideofApple
Explainwhatyouobservewhenyoutasteyourapple.
Taste
Tartness
Sweetness
Juiciness
Crunchiness
4
Apple Genetics
(continued)
Part 5: Comparing Royal Gala, Braeburn, and Jazz Apples
Similaritiesanddifferencesfound:
1. Describesimilaritiesyoufoundamongall3applevarieties.
2. Describedifferencesyoufoundamongall3applevarieties.
Crossbreedingapples
1.
Whichofthethreeappleswasyourfavorite?Why?
2. Whydoapplebreederscrossbreedapplevarieties?
5