Tropical forests 2: Molecular ecology Flashcards
What is molecular ecology?
The use of molecular genetic tools to study ecological questions
What is assessed using molecular ecology?
Genetic diversity within and genetic differentiation among individuals/populations/species
Give six examples of markers that are used in molecular ecology
Allozymes, microsatellites, mitochondrial DNA, nuclear sequences, single nucleotide polymorphisms, whole genomes
What are microsatellites and why are they useful?
Short set of repeated DNA sequences on a chromosome. They have a high mutation rate, allowing the detection of more recent events.
What is mitochondrial DNA?
Small circular chromosome in the mitochondria that encodes genes used in energy production
Why is mitochondrial DNA useful?
It is maternally inherited and does not undergo recombination (can sequence haplotypes), is easy to amplify, and often has a higher mutation rate
What are two disadvantages of the use of mitochondrial DNA?
Genetic introgression between closely related species (passed between newly formed species by breeding). Copies can move to the nuclear genome and form pseudogenes
What are the four steps of the polymerase chain reaction to amplify a material?
1: denaturing (separating strands)
2: primer (short complimentary DNA strands bound to material)
3: polymerase fills in other strand (add nucleotides)
4: purification and sequencing
What is assumed when determining conservation measures?
That we know biodiversity level and what species are present
How can cryptic species be revealed?
Molecular tools e.g. DNA barcoding
What does DNA barcoding use?
A short DNA sequence of the mitochondrial cytochrome gene
Why is the mitochondrial cytochrome gene used in DNA barcoding?
It has sufficient mutational differences to distinguish different species
Why are chloroplast genes used in the DNA barcoding of plants?
Because plant mitochondrial DNA is less variable
What is used in DNA barcoding to detect different species?
The gap in genetic distance
Name three limitations of DNA barcoding
Mitochondrial introgression, variable mutation rates, high divergence can accumulate quickly in bottlenecked populations
What is phylogeography?
The study of the principles and processes that govern the geographic distribution of genealogical lineages
What can phylogeography determine?
Past movements of a species and how they attained their present distributions
Give two examples of trends and periods that have had major effects on the spatial distribution of genetic diversity
Late Pliocene cooling and Pleistocene ice ages
What are refugia?
Habitats in which a population of organisms can survive through a period of unfavourable conditions, especially glaciation
Give three examples of areas of refugia
Iberia, Italy, Balkans
Give an example of two areas that have closely related haplotypes, despite being separated by mountain ranges
Northern and central Europe and the Balkans
