# Monday, September 10, 2012 - PowerPoint PPT Presentation

1 / 13

Monday, September 10, 2012. Purpose of H-W Principle:. The Hardy-Weinberg Principle provides a baseline for comparison & determines whether or not gene frequencies have changed in a population and thus whether (micro)evolution has occurred. Hardy-Weinberg Assumptions.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Monday, September 10, 2012

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

### Purpose of H-W Principle:

The Hardy-Weinberg Principle provides a baseline for comparison & determines whether or not gene frequencies have changed in a population and thus whether (micro)evolution has occurred.

### Hardy-Weinberg Assumptions

• Very large population size

• No migration

• No net mutation

• Random Mating

• No natural selection

### Hardy-Weinberg Equations:

p = frequency of allele 1 in gene pool

q = frequency of allele 2 allele in gene pool

Frequencies can be expressed as decimals (0.4) or percentages (40%)

p + q = 1

### Hardy-Weinberg Equations:

Allele frequency is used to predict genotype frequency (%) for a randomly mating population

Homozygous for allele 1 = p • p = p2

Homozygous for allele 2= q • q = q2

Heterozygous = p • qorq • p = 2pq

p2 + 2pq + q2 = 1

### Hardy-Weinberg Lab

• Instructions dictate initial allele frequencies of:

• p = 0.5

• q = 0.5

• If there are 28 Teddy Grahams in your population, how many should be pp? pq? qq?

.

### Teddy Graham Genetics

• Today you will be helping Teddy Grahams to procreate.

• Reminder of the genetic rules:

• When honey and honey mate, 2

Honey are born

• When honey and chocolate mate,

2 speckled are born

• When honey and speckled mate,

One honey and one speckled are born

• When chocolate and speckled mate,

One chocolate and one speckled are born

### When Speckled and Speckled mate

• Use the allele cards. Each speckled has a p and a q allele

• Pick one allele for each parent to give

• This determines the genes of the first offspring

• Return the cards to the parent and pick again for the second offspring

• Allow 5 generations to mate.

• Fill in the data chart and calculate allele frequencies at the end of 5 generations

• Conduct a Chi Square test to see whether the number of bears of each type you expect to have if allele frequencies did not change, differs from the observed (actual) number of each type you have