Marine Population Genetics

Question 1

The use of population genetics

Answer 1

to quantify patterns of marine species distribution
Introduction to marine population genetic analyses
Types of analysis and marker choice
Genetic variation in place
Genetic variation in time

Question 2

what is marine population genetics?

Answer 2

It is a study of genetic variation within populations and involves the examination and modelling of changes in the frequencies of genes and alleles in populations over space and time

Question 3

applications of marine population genetics

Answer 3

Classic phylogeographic studies-patterns of dispersal and distribution

Population genetics of invasive marine species

Conservation management of species/marine reserves

Management of traded species

Taxonomic decisions

Question 4

Haptotypes

Answer 4

set of alleles e.g. individual collection of specific mutation within a given genetic segment

Question 5

Advantages of using mt-DNA as the standard phylogenetic tool

Answer 5

Primer avaliability
High copy number per cell
High mutation rate
Intrapsecific polymorphism ‘neutral’
Small effective population size
No recombination- can use haplotype distributions and frequencies to infer relationships among populations

Question 6

Disadvantages of using mt-DNA as the standard phylogenetic tool

Answer 6

Only inherited through the maternal line so limitation if there are differences between ales and females

Question 7

Network Analyses

Answer 7

A diagram of haplotype relationships indicating possible mutation pathways between them

Each circle = 1 haplotype

Size is proportional to frequencies
Connecting line show mutational pathways a, lengths = genetic distance

Black squares = missing data

Question 8

Fixation index (Fst) Analyses

Answer 8

Fixation index is a measure of population differentiation (e.g. between different sampling sites)

Often used to calculation pairwise, where every sampling site is compared to all other sampling sites

Can range from 0 (indicating no differentiation between populations) to a theoretical maximum of 1 (highly differentiatial populations)

Question 9

ANOVA Analyses

Answer 9

Analyses of molecular variance (ANOVA) is a method of estimating population differentiation directly from molecular data

Uses phi-statistics which summarise the degree of differentiation between population divisions (haplotype frequency and divergence)

Allows the testing of hypotheses

Question 10

Population Trees Analyses

Answer 10

Uses the Da distance which is the number of net nucleotide substitutions per site between populations, thus taking in account the intra- population variability

Question 11

the main goal of Marine population genetics/Phylogeography

Answer 11

to interpret the historical causes of genetic variation in space (e.g. across oceans)

Question 12

What is Vicariance?

Answer 12

the process of separation of individuals due to environmental events e.g. the rise of the Isthamus of Panama, that can give rise to speciation

Question 13

What is Dispersal?

Answer 13

is the active movement of individuals of a species that give rise to range expansion ans in turn, ultimately speciation

Question 14

What is genetic divergence?

Answer 14

the process in which two or more populations of an ancestral species accumulate independent genetic changes (mutations) through time

often leading to reproductive isolation and continued mutation even after the populations have become reproductively isolated for some period of time

Question 15

Where are Lionfish (Pterios miles) invasive to?

Answer 15

Eastern Mediterranean

Question 16

Possible sources of Lionfish invasion?

Answer 16

-Aquarium release
-Transport by ship ballast water
-Dispersal from an Atlantic source
-Passage through the Suez Canal