P2 Allele Frequency

Question 1

What is the gene pool?

Answer 1

The set of all the alleles in the whole population of a species.

Question 2

What is the allele frequency?

Answer 2

The probability of an allele appearing in the gene pool.

Question 3

What is the Hardy-Weinberg equation used for?

Answer 3

To calculate the frequency of allele pairs:

• p = probability of dominant allele
  q = probability of recessive allele
• when there are only two alleles for a gene: p + q = 1

Question 4

How is the Hardy-Weinberg equation used?

Answer 4

p^2 + 2pq + q^2 = 1

• p^2 = probability of homozygous dominant (AA)
• q^2 = probability of homozygous recessive (aa)
• 2pq = probability of a heterozygous individual (Aa or aA)
• use equation alongside:
  p + q = 1

Question 5

How does the Hardy-Weinberg equation show the phenotypic probability?

Answer 5

• p^2 + 2pq = probability of phenotype from the dominant allele
• q^2 = probability of phenotype from the recessive allele

Question 6

What is the Hardy-Weinberg principle?

Answer 6

• Allele frequencies will remain constant from generation to generation.
• Therefore these conditions must be met:
  1. No mutations
  2. Population isolation with no migration
  3. No natural selection
  4. Very large population
  5. Random mating
• However natural populations are unlikely to meet all of these conditions.