Hardy Weinberg Notes

People caught on to what Mendel said about inheritance.
Someone said dominant alleles would become increasing popular in a population. While that makes sense, it isn’t what actually happens. Hardy and Weinberg separately wrote papers in response to that though process, saying the same thing as each other.
What they wrote was the null hypothesis for evolution in a population. They identified circumstances where evolution won’t happen.
Allele frequencies will persist forever unless something disturbs them.
Dominance or recessiveness does not mean one will be more popular.
Null hypothesis is the 6 -7 conditions that affect the allele frequencies:
1. population must not experience any mutation (change in DNA)
a. Mutation is always happening in a low but constant rate in every population
2. mating must be totally random (no preference based on genotype)
3. reproductive success is completely random (all phenotypes, all gametes, and parents are equally fertile)
4. population must be infinitely large (large enough to avoid sampling errors- genetic drift, sample must be large enough for both alleles to be represented)
a. Small enough population condition might be possible. The number is unknown though.
5. no natural selection occurring in the population
6. no immigration (bringing in new alleles) or emigration (taking alleles with them)
a. Dispersal might be satisfied in islands or mountain tops.
7. All members of the population breed
Hardy- Weinberg equilibrium equation- (p2+2pq+q2=1) where p is the frequency of the dominant allele and q is the recessive allele frequency for a trait controlled by a pair of alleles. P= AA + ½ Aa. Q= AA + ½ Aa. So P+q=1. The 2pq in the equation represents heterozygous.