Population Genetics and Genetic Drift Flashcards
What are the steps for the jellybean simulation?
Take four jellybeans without looking at their color. Write down how many you have of each color. iClicker questions are only about your own jellybeans today.
What are the colors for assorted jellybeans in the simulation?
White (w), pink (p), red (r), orange (o), yellow (y), green (g), maroon (m), black (b).
How many frogs are in the small population simulation?
Two frogs with diploid individuals at a single locus having two alleles (A1, A2).
Define Genetic Drift.
Random changes in allele frequencies due to random events, impactful in small populations.
What is the Hardy-Weinberg Theorem (HWT)?
Frequencies of alleles remain constant in the absence of mutation, migration, and natural selection.
Name some definitions from Chapter 6.
Population genetics, genetic locus, heterozygosity, genetic drift, Hardy-Weinberg Theorem (HWT), fixed allele, genetic bottleneck, founder effect, fitness, relative fitness, and heterozygote advantage.
What do population geneticists study?
Distribution of alleles in populations and causes of allele frequency changes.
What is the key notation for diploid individuals?
Homozygous (alleles are the same A1A1 or A2A2), heterozygous (alleles are different A1A2).
What are the predictions from the Hardy-Weinberg Theorem?
In the absence of selection, migration, or mutation, allele frequencies in the next generation remain the same.
How does genetic drift affect populations?
Causes changes in allele frequencies, with more rapid loss in very small populations.
What is the effect of genetic drift on population size?
Inversely related: large populations have small effects, small populations have large effects.
What is a genetic bottleneck?
A sharp reduction in the size of a population leading to random allele frequency changes.
What is Ne (effective population size)?
The ideal size undergoing the same genetic drift as the population. Ne > 50 prevents severe inbreeding, Ne > 500 prevents severe loss of alleles.
Why is inbreeding a concern in small populations?
Increased homozygosity for deleterious recessive alleles can cause serious reductions in mean fitness, leading to selection.
What does the extinction vortex concept suggest?
Small populations lose genetic variation, increasing the risk of extinction.
