Genetic variation and the founder effect

Why is selective breeding an example of artificial bottlenecking

Selective breeding is an example as mates are chosen who have specific alleles, reduces other alleles available reducing allele of one and over representing another.

How is genetic diversity effected as a result of population bottlenecks

Genetic diversity is decreased as a result of bottle necks as members of the population are killed, removing certain alleles and making others over represented, also encouraging interbreeding.

What is the founder effect and how does it affect genetic diversity

A type of selection that is caused by the ecological separation of a population. A certain allele becomes more frequent within causing the population to change completely. It effects genetic diversity as the populations are small so more chance of inbreeding an certain alleles may get lost.

How can genetic diversity be increased

. No interbreeding

. Migration

. Mutation

How can genetic diversity be decreased

.Interbreeding

.Death

. Non selective disasters

Genetic diversity

The genetic differences between individuals within a population.

Allele frequency

How often a particular allele occurs within a population.

The founder effect stages

. You have an island and a main land, the mainland has a population of organisms

.A few individuals from the main land populate the island

. There may be a higher frequency of one allele in the founder population just by chance

.The population grows, an allele may be lost if individuals fail to produce off spring

.Mutations may occur creating new alleles, the mutation then becomes more common causing the two population on the two lands to look very different.

Problems with founder effect

It is only made up of a small number of individuals, casing a problem with inbreeding

. Have a non-representing sample of alleles from parent population

. Certain alleles may go missing as a consequence, resulting in loss of genetic diversity.

Population bottlenecks

Ecological events that may reduce population sizes dramatically, these disasters are un-selective. Small populations are unlikely to be a representation of original population. By chance some alleles with be over represented and others lost completely.

Similarities of the founder effect and bottlenecking

.Are followed by genetic drift which results in changes in allele frequency

.Initially genetic diversity is lost

. Involves small number of individuals breeding with each other

.May result in a new population which carries alleles that are an unlikely representation of original group.

Differences between founder effect and bottlenecking

Individuals are killed, reducing the choice of mates, in the founder effect individuals are separated ecologically.