Ch 27 - Population Genetics Flashcards
(20 cards)
Fun fact ish: why are cheetah’s dying out?
Not bc birth rate is low.
Issue is inbreeding from when they were endangered. Now they’ve lost a lot of their survival traits
Central issue in population genetics is ________
genetic variation
What branch of biology does pop genetics play a key role in?
conservational biology
def gene pool
conceptually, all the alleles of every gene in a population
- only individuals that reproduce can contribute to the gene pool of the next generation
What are the factors that affect population?
size
geographic location
genetic composition
def polymorphism
observed variation in displayed traits
ex: smiley face spider (pattern looks differen)
______ accounts for 90% of variation in people?
HINT: it’s an acronym
SNP
single-nucleotide polymorphism
on average, a gene that’s 2k-3k in length contains ___ number of diff polymorphic sites
10
What happens if there’s a mutation in a repetitive sequence?
doesn’t matter - genes aren’t doing anything anyway
Variation in the human beta-globin gene:
Hb(a) -> Hb(s)
Hb(a) -> deleted
SNP leads to sickle cell
deletion leads to loss of function
difference between frequency & percent
0 - 1
0% - 100%
what is HW equation
simple mathematical expression that relates allele & genotype frequencies in a pop
what kind of model is HW equation?
null model of evolution; it tells you when evolution is NOT going to happen
HW’s equation = equilibrium - only works under certain conditions. what are they?
infinite number of individuals in the population (not realistic)
all offspring survive (not realistic)
(check book to see if there’s more)
what is the HW equation?
(p+q)^2 = 1, where p+q = 1.
polynom it out: p^2 + 2pq + q^2 = 1
what are genetic mutations?
new genetic variation.
sources:
- sexual reproduction processes
- rare DNA mutations
See table 27.2 for more details
mutagens _____ mutation rate
increase
what’s the relationship between mutation & evolution?
mutational variation provides the raw material for evolution, but doesn’t constitute evolution itself
in other words, natural selection/nature decides which mutations stay and which don’t
rank the likelihood of beneficial, neutral & deleterious mutations
beneficial the least
neutral & deleterious the most likely
mutation alone makes very little change (over 1000 generations, will only see a allele f change from .8 –> .792.
thus, mutation needs _____
selection
