Hardy-Weinberg principle

Question 1

When does evolution occur?

Answer 1

When there are genetic changes in a population over time

Question 2

Define population:

Answer 2

Group of organisms of the same species living together in a defined area and time

Question 3

Define genes:

Answer 3

Code for particular trait carried on chromosomes

Question 4

Define allele:

Answer 4

Form of a gene

Question 5

Define gene pool:

Answer 5

Sum of all the alleles for all the genes in a population (sum of all genetic variation that can be passed on)
- The more variety in a gene pool, the better the population can survive

Question 6

Describe genotype frequency:

Answer 6

• Proportion of a population with a particular genotype
• Usually expressed as a decimal
• Number of individuals with that genotype divided by the total number of individuals in that population

Question 7

Describe phenotype frequency:

Answer 7

• Proportion of a population with a particular phenotype
• Number of individuals in that population with that phenotype divided by the total number of individuals in that population

Question 8

Describe allele frequency:

Answer 8

• Rate of occurrence of a particular allele in a population
• Expressed as a decimal
• Times the population number by two (one on each chromosome pair) then divide it by the total number

Question 9

Describe recessive alleles:

Answer 9

• Some recessive alleles are more common than dominant
• Allele frequencies actually remain the same as long as five conditions are met (Hardy-Weinberg principle)

Question 10

Describe the Hardy-Weinberg principle:

Answer 10

• Allele frequencies will remain the same if the following conditions are met:
  1. The population is large enough that chance events will not alter allele frequencies
  2. Mates are chosen on a random basis
  3. There are no mutations in the genes that affect phenotype
  4. There is no migration
  5. There is no natural selection against any of the phenotypes

Question 11

Describe Hardy-Weinberg calculations:

Answer 11

• The letter “P” is used to represent frequency of dominant alleles
• “q” is used to represent frequency of recessive alleles
• Combination of frequencies of alleles should equal 1.00 (100%)
• q+p = 1.00

Question 12

How to calculate the number of individuals with a specific genotype:

Answer 12

• If you know the population size, N, you can use the following formula to calculate the number of individuals with a specific genotype
• p2(N) + 2pq(N) + q2(N) = N

Question 13

What is the equation for genotype frequencies:

Answer 13

p2 + 2pq + q2 = 1.00