Population Genetics Flashcards
Describe harmful mutations
Harmful mutations and mutations that affect the survival of an organism. They (usually) decrease survival and the ability to reproduce, and therefore are unlikely to be passed onto offspring and can usually be eliminated from a population after the original individual dies.
Explain the founder effect
The founder effect occurs when a population is descended from a small number of colonising ancestors, who were reproductively isolated from the original population. This results in the reduced genetic diversity of new population.
Explain the process of genetic drift
Genetic drift is the process of change in the allele frequencies within a population due to chance or random events, rather than natural selection. This can result in alleles being lost or fixed in the population. Random events such as non-reproduction, random predation, or death can increase or decrease the allele frequencies in the population.
Describe a mutation and how it enters a gene pool
A mutation is a permanent change in the base sequence of DNA. Mutations of the original source of variation as it introduces new alleles into a population, when the mutation is present in the gametic cells of an individual.
Explain the process of natural selection
Natural selection provide selection pressures which act on a population. It is a process with individuals better adapted to their environment due to favourable alleles, tend to survive better and produce more offspring. These individuals then pass the favourable alleles onto the next generation, increasing the allele frequency. This would lead to an increase in the frequency of favourable alleles and a decrease and frequency of unfavourable alleles in a population.
Explain why harmful mutations may accumulate more in small populations rather than larger ones
Small populations have fewer individuals (less alleles) in the population, and the allele frequency is most likely not representative of the original population. Because of small amounts of individuals there is also an increased likelihood of inbreeding. Small populations are also more likely to lead to fixed alleles and death also has a larger proportional effect, leading to a decrease in genetic variation. Large populations have more individuals which acts as a buffer against random deaths, non-mating, and also reduces the chances of inbreeding.
Discuss reasons why a small population may have fewer harmful mutations
A.) individuals in the founding population had a lower proportion of harmful mutations compared to the original population.
B.) individuals with harmful mutations may be removed via genetic drift.
C.) natural selection leading to the removal of harmful mutations from a gene pool.
