# What is derived allele frequency?

## What is derived allele frequency?

A mutation creates a new allele, which after achieving a population frequency of at least 5%, is referred to as the derived allele (the original non-mutated allele is known as the ancestral allele). Under neutral evolution, most derived alleles are expected to be at a low frequency.

## How do you find the frequency of a Punnett square?

This ought to look familiar: it’s our old friend the Punnet’s Square. Allele A or A1 has a frequency of p, and allele a or A2 has a frequency of q. Multiply the allele frequencies to the get the probability of each genotype….

Genotype Expected Frequency
Aa or A1A2 pq + pq (or 2pq)
aa or A2A2 q * q = q2

What is the formula for determining allele frequency?

An allele frequency is calculated by dividing the number of times the allele of interest is observed in a population by the total number of copies of all the alleles at that particular genetic locus in the population.

What is the frequency of the A2 allele?

Therefore, the allele frequency for A1 is 0.9 (18/20) and the allele frequency for A2 is 0.1 (2/20).

### What is variable allele frequency?

In population genetics, the allele frequency spectrum, sometimes called the site frequency spectrum, is the distribution of the allele frequencies of a given set of loci (often SNPs) in a population or sample. Loci contributing to the frequency spectrum are assumed to be independently changing in frequency.

### What is phenotypic frequency?

Relative phenotype frequency is the number of individuals in a population that have a specific observable trait or phenotype. This is an accurate measurement of the amount of genetic variation in a population.

How do you find allele frequency from phenotype frequency?

Allele Frequency

1. Allele frequency is most commonly calculated using the Hardy-Weinberg equation, which describes the relationship between two alleles within a population.
2. To find the number of alleles in a given population, you must look at all the phenotypes present.
3. 1 = p2 + 2pq + q2

How does Hardy-Weinberg calculate allele frequencies?

In the equation, p2 represents the frequency of the homozygous genotype AA, q2 represents the frequency of the homozygous genotype aa, and 2pq represents the frequency of the heterozygous genotype Aa. In addition, the sum of the allele frequencies for all the alleles at the locus must be 1, so p + q = 1.

## How do you find q2 in Hardy-Weinberg?

So, since white is recessive (i.e. bb), and 40% of the butterflies are white, then bb = q2 = 0.4. To determine q, which is the frequency of the recessive allele in the population, simply take the square root of q2 which works out to be 0.632 (i.e. 0.632 x 0.632 = 0.4).

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