Question

What is the H-W principle for a gene with two alleles in a tetraploid?

Answer 1

Hardy–Weinberg principle well-known as the Hardy–Weinberg equilibrium, model, theorem, or law which states that

Allele and genotype frequencies in a people will remain unceasing from generation to generation in the absence of other evolutionary effects.

These effects include mate choice, mutation, selection, genetic drift, gene flow and meiotic drive

The principle is named after G. H. Hardy and Wilhelm Weinberg, who first proved it mathematically. Hardy's paper was focused on exposing the then-commonly held view that a dominant allele would automatically tend to increase in frequency

Tetraploid

Hardy-Weinberg genotype frequencies are used primarily to test for population stratification and other forms of non-random mating.

The Hardy–Weinberg principle may also be widespread to polyploid systems, that is, for organisms that have more than two copies of each chromosome.

Consider only two alleles. The binomial expansion of

(P+q)² and therefore the polyploid case is the polynomial expansion of (p+q)c where c is the ploidy, for example with tetraploid (c = 4):

Genotype	Frequency
AAAA	P4
AAaa	6p2q2
Aaaa	4pq3
aaaa	q4
AAAa	4p3q

Depending on whether the organism is a 'true' tetraploid or an amphidiploid will determine how long it will take for the population to reach Hardy–Weinberg equilibrium.