Lecture 11

Question 1

Population

Answer 1

a localised group of interbreeding individuals that are all from one species so can produce fertile offspring and are reproductively connected to each other most of the time

Question 2

Population genetics

Answer 2

the study of genetic change in biological populations

this modern understanding of genetics and genetic change over time tells us the genetic mechanism by which evolution and natural selection operate

Question 3

Gene

Answer 3

a unit of heritable DNA

Question 4

allele

Answer 4

a variant of a gene

Question 5

Locus

Answer 5

a location on a chromosome

Question 6

Gene pool

Answer 6

the total aggregate of genes in a population at any one time

Question 7

Allele frequency

Answer 7

number of allele copies/ total allele

Question 8

Allele frequencies over time

Answer 8

evolution is the change in allele frequencies in a population over time

we can test whether evolution is occurring in a population by measuring allele frequencies in different generations

in a population that is not evolving, allele frequencies will stay constant over generations
this is the null hypothesis that a locus is not evolving

Question 9

Hardy-Weinberg equilibrium

Answer 9

allele and genotype frequencies will remain constant over generations in the absence of other evolutionary forces

Question 10

Hardy Weinberg equation

Answer 10

p2 + 2pq + q2 = 1.

predicts allele frequencies in a population in Hardy-Weinberg equilibrium

p and q represent homozygous and pq is heterozygous

Question 11

Hardy-Weinberg principle

Answer 11

described a theoretical population that is not evolving

frequencies of alleles and genotypes in a. population gene pool remain constant from generation to generation

provided that only normal rules of inheritance are at work

normal mendelian segregation

normal recombination (exchange of DNA between homologous chromosomes

Question 12

5 conditions for non-evolving population

Answer 12

no natural selection
no mutations
no gene flow
extremely large population size
random mating

Question 13

Polygenic inheritance

Answer 13

a character may be affected by many genes

e.g human skin colour has three genes all contributing to one chracteristic

Question 14

Single genes

Answer 14

generate discontinuos groups such as tall or short but may seem continuous such as human height

this is due to polygenic inheritance

Question 15

Quantitative genetics

Answer 15

many characteristics are determined by multiple genes and environmental effects
- hence phenotypes vary continuously
- these are called multifactorial characteristics
- the study of these genes is called quantitative genetics

Question 16

Importance of quantitative genetics

Answer 16

economic- yields in agriculture

medical- hypertension, cancer, arthritis

Question 17

Genome wide association studies

Answer 17

identify genes associated with multifactorial traits such as diseases