the bean lab: allele frequency

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

Bean

Pop

ulai

ton

0 10 20 30 40 50 600

10000

20000

30000

40000

50000

60000

Growth of Bean Population(10 Generations)

Days10 Generation Forecast

Tota

l Pop

ulat

ion

of B

eans

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 600102030405060708090

100

Allele Frequency over Generations

R Frequencyr Frequency

Days10 Generation Forecast

Pere

ntag

e of

Alle

les

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 Population Fire Breathing Dragon who eats red beans for lunch