Darwin's Theory
The portion of Darwin's theory stating that species change over time.
Despite its importance, this makes up only 2% of the human genome.
When a population has no change in allele or genotype frequencies from one generation it is in this state
What is Hardy-Weinberg Equilibrium?
Genetic drift is more important in these types of populations
What are smaller populations?
A population has these genotype frequencies: fAA = 0.45, fAB = 0.5, fBB = 0.05. This is the allele at a higher frequency.
What is the A allele?
fAA = 0.45 = p2 sqrt(0.45) = 0.67 = p
fBB = 0.05 = q2 sqrt(0.05) = 0.22 = q
The idea that evolutionary change occurs through small incremental steps
What is gradualism?
Although the genomic rate of mutation is high, we do not see many phenotypic changes because most mutations are this.
What is neutral?
F is a measure of this, non-random mating with respect to familial relationships
What is the inbreeding coefficient? or What is the degree to which an individual's parents are related?
This decreases genetic variation within populations but increases divergence between different populations.
What is genetic drift?
A population of sheep is in Hardy-Weinberg equilibrium. The allele for white wool (W) has an allele frequency of 0.19, and the allele for black wool (w) has an allele frequency of 0.81. This is the percentage of heterozygous individuals in the population
What is 31%?
p = 0.19, q = 0.81
heterozygous individuals = 2pq = 2 x 0.19 x 0.81 = 0.31 or 31%
What is populational change?
These two things create genetic diversity.
What are mutations and recombination?
HWE allows us to assume genotype frequencies from these
What are allele frequencies?
This increases genetic variation within populations while decreasing divergence between populations
What is gene flow?
In corn, purple kernels are dominant to yellow. A random sample of 100 kernels is taken from a population in Hardy-Weinberg equilibrium. It is found that 9 kernels are yellow and 91 kernels are purple. The frequency of the yellow allele in this population is this
What is 0.3?
9/100 A2A2 = q2
sqrt(q) = sqrt (0.09) = 0.3 = q
The portion of Darwin's theory that counters higher and lower species
What is common decent?
Many simple traits like eye color are only affected by genotype, but complex traits may also be affected by this
What is environment?
Under HWE for a trait with two alleles, the expected heterozygosity (He) is equal to this
What is 2pq?
This will eventually decrease in a small population facing genetic drift
What is genetic variation?
For pea plants, short stalks are recessive (tt), while long stalks are dominant (TT, Tt). In a population of 100 plants, 45 of them have long stalks, and 9 of them are heterozygous. Is the population in HWE?
What is no?
fTT = 36/100 = 0.36 = q2
sqrt(0.36) = q = 0.6
p = 1 - q = 1 - 0.6 = 0.4
2pq = 2 x 0.6 x 0.4 = 0.48
0.48 x 100 = 48 heterozygotes in HWE, but we only have 9
The parts of Darwin's theory that had opposition or were challenged.
What are natural selection and gradualism?
These can move around the genome and cause duplications, deletions, and inversions from inserting themselves into the genome
What are transposable elements?
This describes non-random mating but only with respect to a specific phenotype
What is assortative mating?
This is the size of an idealized population that would have the same patterns of genetic drift as the actual population.
What is the effective population size (Ne)?
1