genes alleles and inheritance

if a child has the disease and the parents do not then the parents are heterozygous and the disease is recessive 

if a child does not have the disease and the parents do then the parents are heterozygous and the disease is dominant.

if a daughter has a recessive disease and the father doesn't then the disease can not be sex-linked.

if a son had a dominant disease and the mother is homozygous recessive then the disease cannot be sex-linked.

• there should be no immigration or emigration. the gene pool must be isolated and there is no flow of other alleles in or out
• there should be no mutation
• there should be no selection for or against a particular allele
• there should be a large population 
• mating within the population should be random

p + q = 1.0

p2 + 2pq + q = 1

p= dominant allele 

q= recessive allele

Species exist as one or more populations.

A population as a group of organisms of the same species occupying a particular space at a particular time that can potentially interbreed.

predicts that allele frequencies will not change from generation to generation. The conditions under which the principle applies.

The genotype is the genetic constitution of an organism.

The phenotype is the expression of this genetic constitution and its interaction with the environment.