1. The Hardy Weinberg Principle Flashcards
(9 cards)
Define species
Group of similar organism that can reproduce to give fertile offspring
Define population
Group of organisms of the same species living in w particular area at a partcijylst time - potential that they can interbreed
Define gene pool
Complete range of alleles present in population
How often allele occurs in population is called allele frequency - %%% of total population
What is the hard Weinberg principle
It Predicts the frequencies of alleles/ genotypes / phenotypes in a population won’t change from one generation to the next.
This prediction is only true under certain circumstances
•large pop no immigration/ emigration/ mutations / natural selection
•needs to be random mating
What happens if frequencies do change between generations in large population
There’s been an influence of some kind
Allele frequency equation
p + q = 1
p = the frequency of one allele - usually dominant
q = frequency of other allele - usually recessive
The total frequency of all possible alleles for a characteristic in a certain population is 1.0 - 100% so recessive and dominant allele must add up to 1
If allele frequencies add up to more than 1 then they’re not the allies for same gene
If add up to less than 1 there’s more than 2 alleles for that gene
Genotype frequency equation
p2 + 2pq + q2 = 1
Total frequency of all possible genotypes for one character in certain population is 1.0
3 genotypes : homozygous recessive/ homozygous dominant and heterozygous = all add up to 1
What does the genotype frequency equation mean ?
p2 = frequency of homozygous dominant
2pq = frequency of heterozygous
q2 = frequency of homozygous
What can the genotype frequencies then be used to work out ?
Phenotype.
Eg genotype of plant Rr where R codes for red flower which is dominant over r - the phenotype would be red flowers
