Solved by a verified expert:GeneticInheritance
Margaret E. Vorndam,
M.S.Version 42-0061-00-01
LABREPORTASSISTANT
Thisdocumentisnotmeanttobeasubstitute
for
aformallaboratoryreport.TheLabReport Assistantissimplyasummaryoftheexperiment’squestions,diagramsifneeded,anddatatables
that
shouldbeaddressedinaformallabreport.
Theintentistofacilitatestudents’writing
oflabreportsby providing
this informationin an editable
filewhichcan be sentto an instructor.
DataTable
1: PunnettSquarefor F1 Cross – Expected GeneticOutcomes
F1Parent,genes:
(studentto
fillin the blanks)
alleles >
alleles v
F1 Parent, g
enes:
__________(student fill
in blank)
DataTable
2:Results of F1 Cross
Observed Phenotypes of F2Progeny
# green plants =
# white plants
=
Total # plants
Petri Dish 1 >
Petri Dish 2 >
Total
Data
Table 3: Dihybrid Cross in Corn
–Results of P Cross
P = purple,
p =yellow
S = smooth, s =
wrinkled
(student
to fillin all blanks )
Generation
Expected Alleles
Expected Alleles
P >
dominant xrecessive
_ppss_
F1Progeny >
Frequency >
Data
Table 3A: PunnettSquarefor
F1 Dihybrid Cross
Expected Genotypic Outcomes
(student
to fillin)
Parent
1 F1–can produce
thesegametes: (studentto
fillin)
Parent2F1 –canproduce
thesegametes:
>
ShadedportionaboverepresentstheF2progeny
genotype and phenotype.Student
to fillin.
Data
Table 4: Dihybrid Cross in Corn
–Results of F1 Cross in F2 Progeny
Phenotype of
Progeny
(What they look like –word description)
Genetic Designations possiblefor this Phenotype
e.g., PPSS
Predicted Allelic
Frequency
(Expected Ratio)
Number of this PhenotypeTotal Counted:
100 (Observed
Number)
Actual Allelic
Frequency
(Observed
Ratio)*
e.g.,Yellow, wrinkled
ppss
* Actual
Allelic Frequency (Observed Ratio)
= Number of this PhenotypeTotal
Counted ¸ 100kernelstotalcounted
DataTable 5: ?2Goodness of FitTest
for FPhenotypicResults from FCorn Cross
2 1
Phenotype
Description
of
F2Progeny from
Table 4
Observed
Number fromTable 4
Observed
Ratio fromTable 4
Expected Ratio from
Table 4
* Expected Number,calculated
** [Observed
No. – Exp. No.]2
÷Expected No.
e.g.,Yellow, wrinkled
? Sum ofcolumn =
c2,Chi-squarevalue
***
>
* Expected
Number,calculated
= ? Sum of Observed
Number x Expected Ratiofor that
phenotype
** = (Observed
number – Expected number,calculated)
square
÷ Expected
Number,calculated
*** c2,Chi-squarevalue=?Sumof(Observednumber–Expectednumber,calculated)
squared ÷ Expected
Number,calculated
DataTable 6: Summarizationofc2Good FitResults
for FCorn Cross
1
c2value fromTable
5 =
Valueat 3 Degrees of Freedom that is closestto
c2
value =
What is the Fit Probabilityat thetop of thecolumn in which thevaluewas
found?
What is the % of probability that the observed
results match theexpected
results?
(MultiplyFit Probability
by 100)
Readingat thetop
of theTable, this Fit Probability indicates that theexpectedresults
hypothesis is a
Good Fit Poor Fit
Circle thecorrect choice above
Exercise
1: F1 Hybrid Cross
A.Expectedphenotypicratioofgreentowhiteprogeny: CalculationofExpectedRatio
(Frequency) = =Total Number of (Color) Seedlings ÷Total
of All Seedlings.
B. If 320 F2offspring
resulted from this F1cross, how
manywould be green?
White?
DISCUSSION
A.Did theresults support orrefute
thehypothesis? Explain.
B. How
similar are the observedto
theexpectedresults from the PunnettSquare?
C. If theresults are not
similar, how might the differencebeexplained?
D.WillamonohybridF1crossincornyieldthesameratioofexpectedphenotype
inprogenyas
for thetobacco seedlings? Why or why
not?
E. Ifavailable,
compareyourF2seedlingdatatothoseofyourclassmates.Aretheoutcomeratios the same? Why might using a larger
number of seedlingsto determine
this outcome be wise?
Exercise
2: Dihybrid GeneticCrosses
PROCEDURE
1. Basedonwhatyoucanconcludeaboutitsgeneticmakeupwhentoldthatthecornplant parentcross(P)picturedinFigure2isbetweenacompletelydominantplantandacompletelyrecessive plant,
a. Constructandrecordahypothesisaboutwhatthegeneticmakeupandthefrequencies oftheallelesfortheF1 progenyplantsinthedihybridcrossofcornwillbe.Recordyour
hypothesis here:
b. IftheseF1progenyaremated,whatwillbetheresultingallelic
frequencyfortheF2
progeny?Record
thishypothesis here:
RESULTS
A.Whatarethetwohypotheses
thatyoumadeabouttheallelicfrequenciesofprogenyproducedby
the crosses:
P x P?
F1x F1?
B. Based
on
whatyou
knowaboutphenotypesandFigure2,for
the
P
generation, what is
the
corn plant genotype on
each
cob containing the
P
corn kernels?
One iscompletely dominant, so itsgenotype is
One
iscompletelyrecessive,
so itsgenotype is .
C. WoulditmakeadifferenceintheoutcomeofthiscrossifthegenotypeofoneparentisPPss and the other is ppSS?
D.Fromthephenotype
ofthekernelsoneachPgenerationcobwhatwouldthepredicted
genotype of any F1plant
be?
E. Giventhe2nequationpredicthowmanydifferentgeneticoutcomeswillbepossiblefroman
F1cross
resultingin theF2generationin
a dihybridcorn cross.
F. IfaF2corncobresulting
fromthisF1crosscontained
563seeds,howmanyoftheseeds
wouldyouexpectto look like
the F1parent?
QUESTIONS
A.How
well do the predictedresults match the actualresults inTable 4?
B. Based
onthePunnettSquarepredictions,canastatementbemadeastowhetheryourhypotheses
are supported orrejected? Which and why?
C. DihybridF1crossesresultinapredictableF2progenyphenotypicfrequencythatholdstrue
universally. Based on the
Expected outcome, what is it?
D.Ifyour
results are not asexpected why
might there be differences?
E. Whatapplicationsmightthistypeofgeneticinvestigationhave?Howmighttheinformation
be applied medically?
Exercise
3: Chi-square and Hypothesis Testing
QUESTIONS
A.Whatcanbeconcluded
aboutyourprediction
ofexpectedF2progenyphenotypicoutcome from
the F1cross?Was it closeto the observed
outcome?
1
B. Howmightthec2testforfitnessbeusedinotherways?TryitonthetobaccoseedlingF
cross,for
instance.
C. Inatypicalcrosswhereaparentwithacompletelydominanttraitismatedwithaparent
exhibiting acompletelyrecessivetrait,whatistheexpectedgenotypicoutcomeandallelic frequency
for the F1progeny?
Give anexample.
D.InatypicalcrosswherehybridF1parentsaremated,whatistheexpectedgenotypicoutcome and allelic frequency of the F2progeny?
Give anexample.
E. FortheF2progenyproducedfromatypicalF1hybridmating,howmanytotallyrecessive individualswould be produced if
the progenytotal
populationis six offspring?
What if the progeny populationwas
20?
50?
1,000?
F. Excluding
factorssuchassex-linkedgenes,incompletedominance
orepistasis,etc.,willthe above cross
resultsvary if differentorganisms
are used, such as dogs or tulips? Why or why
not?
G.
Howwillfactorssuchassex-linked genes,incompletedominance,orepistasis,
etc.,affectthe
expected outcomes that
were
investigatedabove?
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