Hardy-Weinberg Calculator – Allele Frequency and Chi-Square

Hardy-Weinberg Frequency and Chi-Square Test

Hardy-Weinberg Equilibrium and Chi-Square Formula

Formula

$$p = \frac{CH + 0.5 \cdot H}{CH + H + RH} \\[5pt] q = \frac{RH + 0.5 \cdot H}{CH + H + RH} \\[10pt] E_{CH} = p^2 \cdot N \\ E_H = 2pq \cdot N \\ E_{RH} = q^2 \cdot N \\[10pt] \chi^2 = \frac{(CH – E_{CH})^2}{E_{CH}} + \frac{(H – E_H)^2}{E_H} + \frac{(RH – E_{RH})^2}{E_{RH}}$$

Where:

$$CH$$ = number of homozygous dominant individuals
$$H$$ = number of heterozygous individuals
$$RH$$ = number of homozygous recessive individuals
$$N$$ = total individuals = CH + H + RH
$$p$$, $$q$$ = allele frequencies
$$E_{CH}$$, $$E_H$$, $$E_{RH}$$ = expected genotype counts
$$\chi^2$$ = chi-square value for deviation from equilibrium

The Hardy-Weinberg principle predicts genotype frequencies in a population under ideal conditions (no mutation, migration, selection, or genetic drift). This calculator allows you to input observed counts of dominant, heterozygous, and recessive individuals to determine allele frequencies (p and q), expected genotype frequencies, and whether the population deviates from equilibrium using a chi-square test. It is useful in population genetics, evolutionary biology, and academic research.

9 thoughts on “Hardy-Weinberg Equilibrium Calculator”

Yurany Granada says:

09.06.2021 at 23:19

Buenas tardes, quiero saber como debo citarlos. Gracias

Adriana Mena says:

07.06.2021 at 16:16

How are the df calculated?

Monica says:

04.11.2022 at 14:15

df = number of classes compared – no. of parameters estimated – 1.

Oladejo Aliu Abiola says:

03.04.2021 at 15:10

How do you calculate the expected value for the alleles

Daniel says:

28.07.2020 at 18:51

Si una enfermedad es recesiva y la frecuencia del alelo que la genera es de
0,08, ¿cómo serán las frecuencias genotípicas?

Nada says:

25.07.2020 at 17:21

I have one question please, the equation was as follows;
ECH = pfreq * pfreq * (CH + H + RH)
yet you have used the frequency of the rare allele in the following example ,
Step 3 : Expected CH

Expected CH =

= 0.78 * 0.2121 * (21 + 10 + 2)

can you explain why, please?
Plus,
what do you mean exactly by the following;
chi2 = chi1 + chi2 + chi3