population genetics Flashcards
define selection
process by which organisms are better adapted to the environment survive and breed to pass on favourable alleles to subsequent generations
define genotype
alleles of a gene organism posseses
define population
group of the same species occupying a particular space at a particular time and can interbreed
define gene pool
all the alleles of all the genes of all the individuals in a population at a given time
define allelic frequency
the number of times an allele occurs within the gene pool
what are the 5 assumptions of the Hardy Weinberg principle
- model is large
- random mating
- no selection (alleles are equally likely to passed onto the next generation)
- has no mutation
- no emigration or immigration (flow of alleles into or out of the population)
define variation
the differences that exist between individuals
define polygene
large number of genes that have a combined effect
explain the 3 causes of variation due to genetics
mutation
- difference in bases = new a/a = new protein = different/advantageous characteristics
meiosis
- independent segregation
- crossing over
random fertilisation
- each sperm is genetically different = sperm that fertilises egg is different to others due to meiosis