5: Genes in Populations Flashcards
What is genotype frequency
Freq of a particular one-locus genotype in a population
What is allele frequency
Freq of a particular allele in a population
Formula for the freq of M
Formula for the freq of m
M = P + 0.5*H = p
m = Q + 0.5*H = q
What are P, H and Q
P = freq MM
H = freq Mm
Q = freq mm
What are p and q
p = freq M
q = freq m
Formulas for freq of MM, Mm, and mm
MM = p^2
Mm = 2(p)(q)
mm =q^2
What is Hardy-Weinberg Equilibrium
a relationship between allele and genotype frequencies established by random mating that can remain constant from one generation to the next
How many generations before we’re in HWE
After just one generation of random mating
Equations for P, H, Q under hardy-weinberg
P = p^2
H= 2pq
Q = q^2
What do we mean by ‘forces that disrupt HWE’
Things that change allele or genotype frequencies across generations or prevent P=p^2, H=2pq, Q=q^2 from being a good approximation
What is HWE used for
Making predictions - not perfectly adhered to
If values deviate a lot from HWE can indicate errors in genotyping
How would we reduce frequency of the m allele
Selecting only MM and Mm to become parents
Slide 17
Good example
What forces can disrupt HWE
Selection
Migration
Random drift
Non-random mating (inbreeding and outbreeding)
What is selection
Favoring certain genotypes to become parents; changes allele and genotype frequencies across generations
