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THE BEAN LAB:ALLELE FREQUENCY
THE BEAN ALLELE FREQUENCY LABPurpose: The following pictures are a guide to show one example of how the allele frequency could change in a population due to a genetic disorder.
Setup: The three types of beans (red [RR], pinto [Rr] and white [rr]) will be used to represent a population of individuals with a certain trait. If an individual has the recessive phenotype (rr) then there is a 50% chance of surviving to reproduce. Being a carrier of the trait (Rr) has no bearing on mortality.
The 2012-13 class has gone through the lab and developed a set of instructions to go along with the following pictures to help walk you through how to do the lab.
White, rr
(16)
Red, RR
(16)
Pinto, Rr
(32)
Slide #1
R and r frequency = 16 + 16 + 3264 +64
White, rr(8)
Red, RR(16)
Pinto, Rr(32)
Slide #2
The Dating Game
Slide #3
Who got married to who from this Parent Generation (P)
Slide #4
The offspring of those couple, now known as the First Generation (F1).
Slide #5
How did we get these numbers of beans?
How did we get these numbers of beans?
Red, RR (37) Pinto, Rr (54) White, rr (21)
Slide #6
Red, RR (37) Pinto, Rr (54) White, rr (11)
Slide #7
Slide #8
Slide #9
Slide #10
Slide #11
Red, RR (82) Pinto, Rr (92) White, rr (30)
Slide #12
Red, RR (82) Pinto, Rr (92) White, rr (15)
Slide #13
Slide #14
Slide #15
Slide #16
Red, RR (172) Pinto, Rr (166) White, rr (38)
IF WE CONTINUED ON THIS PATH,
WHAT SHOULD THE NEXT SLIDE SHOW?
Slide #17
Red, RR (172) Pinto, Rr (166) White, rr (19)
DATA ANALYSIS
0 2 4 6 8 10 12 14 160
50
100
150
200
250
300
350
400
Bean Population Growth 4 Generations of Beans
Days
Be
an
Po
pu
lait
on
0 10 20 30 40 50 600
10000
20000
30000
40000
50000
60000
Growth of Bean Population(10 Generations)
Days10 Generation Forecast
Tota
l P
op
ula
tion
of
Bean
s
What is happening to the overall bean population?
Why is this happening to the OVERALL bean population?
Could we expect this pattern to continue indefinitely?
What factors could stop this pattern?
0 2 4 6 8 10 12 140
10
20
30
40
50
60
70
80
90
100
Growth and Decline of R/r Frequencies
R Fre-quency
Days 4 generagtions of Beans
Perc
enta
ge o
f the
Pop
ulati
on
0 10 20 30 40 50 600
10
20
30
40
50
60
70
80
90
100
Allele Frequency over Generations
R Frequencyr Frequency
Days10 Generation Forecast
Pere
nta
ge o
f A
llele
s
OTHER QUESTIONS ON BEAN EVOLUTION
* Will the white beans ever completely disappear at this rate?
* What are some scenarios that could happen to cause the white beans to completely disappear?
* The mechanism of evolution that this lab demonstrates is ______ because of ________.
OTHER MECHANISMS THAT COULD AFFECT ALLELE FREQUENCY
MIGRATION (GENE FLOW)
Original Population
New First Generation Reproduction Populations
MATE SELECTION
Original Parent Pairs New Parent Pairs
SMALL POPULATION + CHANCE EVENT – DANGEROUS MUTATION
Original Population Reproduction Population
INTRODUCTION OF A PREDATOR
Original PopulationFire Breathing Dragon who
eats red beans for lunch
