Variation & Selection in Populations (+covid) Flashcards
Population definition
Population - a group of interbreeding (mating) individuals of a single species living in the same time and place
Gene pool definition
Gene pool – the total of all alleles carried in all members of a population
Sample definition
Sample – a number of individuals used to make inferences (conclusions) about the entire population
Phenotype frequency definition
Phenotype frequency – proportion of individuals in a population that have a particular phenotype.
Genotype frequency definition
Genotype frequency – proportion of individuals in a population that carry a particular genotype
Genotype frequency formula
A gene with two alleles (A and a) in a population of 20 individuals (for example)
For example, homozygous dominant genotype frequencies = genotype (homozygous dominant) / population
Each genotype frequency added together equals to??
Each frequency set always adds up to __1 (or 100%) genotype.
100% of the phenotype = ???
recessive phenotype + (dominant + heterozygous) phenotype = 100 % of
the phenotype
The homozygous dominant genotype and the heterozygous genotype both display the dominant allele as the phenotype.
Allele frequency definition
Allele frequency – proportion of gene copies in a population that are of a given allele type. (The amount of specific allele in the given population).
How many allele does one gene have??
Each gene has 2 alleles.
For example: Allele frequencies: in 20 people, there are a total of 40 alleles (each person has 2 alleles at each location).
What are the 5 simplifying assumptions of The Hardy-Weinberg Law (eq.)?
1) Very large populations,
2) Individuals mate at random
3) No new mutations appear,
4) No migration into or out of the population
5) Genotypes have no effect on ability to survive and transmit (pass) alleles to the next generation
(no effect, able to reproduce)
How likely it is that 5 simplifying assumptions of The Hardy-Weinberg Law are always met?
This is very unlikely to occur unless it is controlled (in lab settings)
Hardy-Weinberg proportions can be expressed as equations. What are the 2 equations?
p + q = 1
p = frequency (A) q = frequency (a)
p^2 + 2pq+ q^2 = 1
So then… p^2 = AA 2pq= Aa q^2 = aa
Hardy Weinberg provides a starting point for modeling actual populations, but
actual populations always deviate slightly, because?
(1) . There is selection (some individuals with specific alleles more likely to survive and reproduce in the environment, while others die)
(2. ) Don’t always mate randomly
(3. ) mutations occur
(4. ) We migrate
(5. ) deleterious (harmful) alleles do affect fitness (reproductive success)
Why a population is evolving according to Hardy Weinberg?
Because we have deviations from Hardy Weinberg law
Which s-re gives the virus its name corona? Its characteristics?
The SARS-CoV-2 are spherical with S proteins (spikes) protruding (come through) from the surface. The spikes give the virus its name crown, or corona. Spikes assist the virus in identifying and entering the host cells.
The spikes come from the nucleocapsid and go through the envelope (membrane).
