Lecture 1 - What is population genetics Flashcards Preview

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Flashcards in Lecture 1 - What is population genetics Deck (18)
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1

Define allele

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

2

Why doe understanding micro-evolutionary process matter?

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

3

How is population genetics studied?

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

4

What is evolution

A change of allele freguencies in a population

5

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

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

6

What are the features of mutation?

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

7

What are the features of genetic drift?

-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)

8

What are the features of selection?

-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

9

What are the features of gene flow?

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

10

Define phenotype

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

11

Define Genotype

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

12

Define Genetic locus

a stretch of DNA in the genome

13

Define Gene

a stretch of DNA coding for a protein or functional RNA

14

What is mendels first law?

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

15

What is a dominant allele?

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

16

What is a recessive allele?

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

17

What is a co-dominant allele?

Alleles are co dominant when the heterozygotes have an intermediate

18

Is dominance a continuous or determinate scale?

Dominance occurs on a continuous scale