The Bean Allele Frequency Lab • Purpose: 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.
Slide #1 • White, rr • (16) • Red, RR • (16) • Pinto, Rr • (32) R and r frequency = 16 + 16 + 32 64 +64
Slide #2 White, rr (8) Red, RR (16) Pinto, Rr (32)
Slide #3 The Dating Game
Slide #4 Who got married to who from this Parent Generation (P)
Slide #5 The offspring of those couple, now known as the First Generation (F1).
Slide #6 Red, RR (37) Pinto, Rr (54) White, rr (21)
Slide #7 Red, RR (37) Pinto, Rr (54) White, rr(11)
Slide #11 Red, RR (82) Pinto, Rr(92) White, rr(30)
Slide #12 Red, RR (82) Pinto, Rr (92) White, rr(15)
Slide #16 Red, RR (172) Pinto, Rr(166) White, rr (38)
Slide #17 Red, RR (172) Pinto, Rr(166) White, rr(19)
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?
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 ________.
Migration (Gene Flow) New First Generation Reproduction Populations Original Population
Mate Selection Original Parent Pairs New Parent Pairs
Small Population + Chance Event – Dangerous Mutation Original Population Reproduction Population
Introduction of a Predator Fire Breathing Dragon who eats red beans for lunch Original Population