population genetics

Question 1

what is population genetics

Answer 1

The study of genetic variation within populations

Via the frequency of genes and alleles

There is a huge variation within populations at the nucleotide level

Question 2

what is population

Answer 2

A group of individuals of the same species living in a specific region at the same time

Refers to individuals who interbreed and produce viable offspring

Question 3

what are the 4 factors affecting population size

Answer 3

Birth
Death
Immigration
Emigration

Question 4

the set of genes is a population called what

Answer 4

gene pool

Question 5

how does a population evolve

Answer 5

changes in the gene pool

Question 6

what principles are used to understand the genetic composition of a population

Answer 6

mendelian principles

Question 7

measuring genetic variation

Answer 7

How to measure the numbers of genotypes and alleles in a population

Need to be able to tell the difference at the phenotype level

Differences maybe in coding or non-coding DNA e.g polymorphisms used for forensics

Question 8

what is a frequency

Answer 8

a proportion or percentage usually expressed as a decimal fraction

Question 9

what happens when there are large populations where it is not possible to sample all individuals

Answer 9

a representative sample is usually taken

Question 10

how do you calculate the genotypic frequency

Answer 10

we add up the number of individuals possessing the genotype and divide by the total number of individuals in the population

Question 11

For a locus with 3 possible genotypes, AA, Aa and aa, the frequency of each genotype (f) is:

Answer 11

f(AA)= number of AA individuals / N
• f(Aa)= number of Aa individuals / N
• f(aa)= number of aa individuals / N
The sum of all the genotypic frequencies always equals 1

Question 12

what is passed from generation to generation within a population

Answer 12

alleles

Question 13

how is allele frequency calculated 1

Answer 13

Can be determined from the genotype frequency

p= F(A)= f(AA)+ ½ f(Aa)

q= F(a)= f(aa)+ ½ f (Aa)

If a locus only has two alleles the frequencies are usually represented by p and q. p+q = 1

Question 14

how is allele frequency calculated 2

Answer 14

determined by couting observed alleles and then calculating the frequency

Frequency of an allele = number of copies of the allele / Number of copies of all alleles at locus

Question 15

what are the two mendelian laws

Answer 15

the law of segregation

the law of independent assortment

Question 16

the law of segregation

Answer 16

states that allele pair separate during gamete formation and randomly unite at fertilisation

Question 17

the law of independent assortment

Answer 17

states hereditary factors assort independently during gamete formation

Question 18

relationship between genotype and allele frequencies

Answer 18

the Hardy Weinberg Law is a mathematical representation of the relationship between genotype and allele frequencies in an ideal population