genetic drift and flow9C Flashcards
genetic drift
Genetic drift involves changes to a population’s allele frequencies due to sudden and random occurrences
example of genetic drift
Examples include natural disasters or random movement to colonise a new population.
Types of genetic drifts
Bottleneck effect
Founder effect
What is the bottle neck effect
When a large portion of a population is wiped out due to a random event such as natural disaster
Only a small number of individuals remain in the gene pool and does not represent the original population
Loss of genetic diversity
Increase change of inbreeding
What is the founder effect
Occurs when a small number of individuals colonise a new region and start a new population
This new population is known as colonising or founder population
The founding population has a small gene pool and low genetic diversity
Does not represent original population
The colonising population is exposed to different selection pressures as the original population
Mutations may arise forming new alleles
How does genetic drift increase the risk of inbreeding, and what are the consequences?
Genetic drift can increase the chance of inbreeding by reducing genetic diversity, which limits the available gene pool. This can result in harmful alleles remaining in the population, leading to negative effects such as lower reproductive success and higher susceptibility to diseases.
What is the effect of genetic drift on genetic diversity?
Genetic drift reduces genetic diversity, leading to an increased chance of inbreeding, which can keep harmful alleles in the gene pool. This results in a lower adaptive potential, making the population more vulnerable to new selection pressures.
What is an example of the impact of genetic drift on a species?
An example is the cheetah population, which narrowly escaped extinction at the end of the last ice age around 20,000 years ago. The loss of genetic variation in cheetahs has led to issues such as sperm abnormalities, sensitivity to disease, and high cub mortality rates.
Mechanisms of genetic drift and the consequences
- bottle neck effect which reduces genetic diversity through the removal of alleles due to random events eg. natural disaster
2.founder effect which reduces genetic diversity through the establishment of a new population with a small unreperesentative sample of the original populaiton.
Gene flow
the introduction or removal of alleles from a population due to migration or interbreeding
How does movement into a population affect genetic diversity?
Movement into a population (immigration) brings new alleles, which can increase genetic variants and overall diversity within the population.
What is the difference between immigration and emigration in terms of allele exchange?
Immigration refers to individuals moving into a population, bringing new alleles that can increase genetic diversity. Emigration refers to individuals leaving a population, which can result in the loss of alleles from that population.
How can the exchange of alleles through movement affect a population?
The exchange of alleles through movement (immigration and emigration) can increase genetic diversity by introducing new variants into a population or decrease diversity by removing alleles when individuals leave.
What effect does gene flow have on genetic variation in a population?
Gene flow can either increase or decrease genetic variation. Immigration increases genetic diversity by introducing new alleles, while emigration decreases genetic diversity by removing alleles from the population.
How does the size of a population affect the impact of gene flow?
Gene flow can have a bigger impact on smaller populations than on larger populations. In smaller populations, the introduction or removal of a few alleles can significantly alter the population’s genetic makeup.
What happens to genetic diversity when immigration and emigration occur?
Immigration increases genetic diversity by adding new alleles to the population, whereas emigration decreases genetic diversity by removing alleles from the population.
an organism has undergone bottleneck effect multiple times and then underwent a founder effect.
a. what happens to the genetic diveristy
b. applying your knowledge of immunity, what might happen if a transplantation is done between these speccies assuming that there is so much less genetic variation to the point where they are almost clones of each other
a. Genetic diversity would be significantly reduced. The bottleneck effect reduces genetic diversity by causing a dramatic decrease in population size, leading to a loss of many alleles. If this happens multiple times, even more genetic variation is lost. The founder effect further reduces genetic diversity when a small group from this already reduced population establishes a new population.
b. If a transplantation is done between these species with very low genetic variation, the risk of immune rejection is greatly reduced. This is because the immune systems of the nearly genetically identical organisms would be less likely to recognize transplanted tissues as foreign, making them almost like “clones.” The lack of genetic variation means that the antigens on the cells are likely to be very similar, reducing the likelihood of an immune response.
bottleneck vs founder effect
