Lecture 1 - What is population genetics

Question 1

Define allele

Answer 1

a varient of a gene (or more generally of a genetic locus)

Question 2

Why doe understanding micro-evolutionary process matter?

Answer 2

Evolutionary history
Conservation Biology
Medicine
-genetic mapping of disease
-disease dynamics
Forensic analysis
Breeding of domestic plants and animals

Question 3

How is population genetics studied?

Answer 3

Historically - was a theory rich and data por subject

Now - data rich due to more powerful molecular methods, but theory needed to make sense of the data

Question 4

What is evolution

Answer 4

A change of allele freguencies in a population

Question 5

What are the four key processes involved in evolution? (In order to change allele frequencies)

Answer 5

Mutation
Genetic drift 
Selection 
Gene flow between populations 
(all act together in thre real world)

Question 6

What are the features of mutation?

Answer 6

• all genetic variation occurs by mutation
• random process
• increases genetic diversity
• very low frequency

Question 7

What are the features of genetic drift?

Answer 7

• high frequency
• random changes in allele frequency from one generation to the next
• reduces genetic diversity
• important in small populations (where there is not much allele diversity)

Question 8

What are the features of selection?

Answer 8

• Directional process
• Acts on fitness differences of genotypes (requires phenotype variation with a genetic basis)
• Leads to adaptation
• usually reduces genetic variation, however disruptive selection increases genetic variation

Question 9

What are the features of gene flow?

Answer 9

• depends on the structure of a population e.g. Migration: reduces divergence between populations
• can restore some genetic variability

Question 10

Define phenotype

Answer 10

a visible or measurable trait or series of traits in an individual

Question 11

Define Genotype

Answer 11

the combination of alleles at a genetic locus or set of loci in an individual

Question 12

Define Genetic locus

Answer 12

a stretch of DNA in the genome

Question 13

Define Gene

Answer 13

a stretch of DNA coding for a protein or functional RNA

Question 14

What is mendels first law?

Answer 14

Segregation
-individuals have a pair of alleles for a given trait and these segregate separately into gametes
-one allele is passed on randomly from each parent to their offspring
P1: Yellow and Green
F1: 100% yellow
F2: 3/4 Yellow, 1/4 Green
F3: 1/4 Yellow F2 (YY) -> 100% Yellow
-2/4 Yellow (Yy) -> 3/4 Yellow, 1/4 green
-1/4 Green (yy) -> 100% Green

Question 15

What is a dominant allele?

Answer 15

An allele is dominant when the associated phenotype is expressed in the homozygous or heterozygous state

Question 16

What is a recessive allele?

Answer 16

An allele is recessive when the associated phenotype is only expressed in the homozygous state

Question 17

What is a co-dominant allele?

Answer 17

Alleles are co dominant when the heterozygotes have an intermediate

Question 18

Is dominance a continuous or determinate scale?

Answer 18

Dominance occurs on a continuous scale