Bio 2-L17- Principles of Population genetics

how does genetic variation arise?

due to mutation and sexual reproduction which results in recombination

what are homologous chromosomes?

chromosomes that are closely related in sequence and match up during meiosis

what is a locus?

fixed position on chromosomes- comparing them we can see alternate versions ALLELES

what are alleles

alternate versions of the DNA sequence that occur at the same locus

types of genetic variation in diploid population

1. single nucleotide variant-

2. by insertion or deletion

what is genotype?

the genetic material possessed by an indium at a given locus

how is allele frequency calculated

ie for allele A= allele count ie 3/total number of alleles

how is genotype calculated

ways yo could describe gene pools?

1. allele frequency

2. genotype frequency

how are allele frequencies calculated given the genotypes?

nA= 2nAA + nAb

nB=2nBB+nAb

frequency is F(A)=F(AA)+F(AB)/2

F(B)=F(BB)+F(AB)/2

what does hardy Weinberg equilibrium show?

It demonstrates that allele and genotype frequencies in a population remain constant from generation to generation in the absence of evolutionary influences.

what does the hardy Weinberg equilibrium require?

1. random combinition and random mating

2. no changes in allele frequencies between generations

3. no mutation, no selection, no gene flow

4. large populations

what are some violations on hardy Weinberg?

1. violations to random mating- this isn’t true

2. mutations- change allele frequency

3. genetic drift- small population effects on allele frequencies- founder effect or population bottleneck

4. gene flow- genetics from one population to another

5. selection- changes allele frequencies due to differential survival and reproduction of individuals.

what is the hardy Weinberg principle formula?

p² + 2pq + q² = 1

why does non random mating not change allele frequencies?

Non-random mating affects the genotype frequencies but not the overall allele frequencies in the population.

• This is because it does not introduce new alleles or remove them; it simply rearranges the existing combinations.