33. Molecular phylogeny Flashcards
Explain molecular evolution
Molecular evolution - based on molecular clocks
Explain molecular clocks
The rate of molecular sequence evolution is constant over time and among evolutionary lineages
It is based form observations on:
- haemoglobin
- cytochrome c
- fibrinopeptides
How is the molecular clock used and calculated?
What are the limitations of molecular clock
RLE where molecular clock helped
Dating the origin of HIV → descendant from viruses that infect chimpanzees / other primates; HIV spread to humans more than once
Linear relationship for the past 20 years → apply the trend to past
What are morpholigical and molecular homologies?
What are orthologues?
Orthologues - ancestral genes which underwent speciation at some point and produced two different genes, found as a single copy in the genome and are homologous between species
RLE: α and β haemoglobin
Orthologous genes are widespread and extend across many widely varied species, ex.: humans and mice diverged 65 mil years ago, 99% genes are orthologous→ useful study organisms
what are paralogues?
Paralogues - gene sequences which duplicate in the genome, can diverge within species and evolve into different functions
Ex: glopbin protein family
What is the importance of gene duplication in evolution?
Paralogues - gene sequences which duplicate in the genome, can diverge within species and evolve into different functions
Ex: glopbin protein family
What is tree reconcilation?
Phylogenetic tree reconciliation - widely used approach for analyzing the inconsistencies between the evolutionary histories of genes, and the species through which they have evolved.
What is horizontal gene transfer?
Common in bacteria
What are xenologues?
Xenologous - genes which result form horizontal gene transfer
How horizontal gene transfer influences the evolution of domains?
With horizontal gene transfer the evolutionary path should be like a network instead of linear relationships
What are the methods to identify horizontal gene transfer?
Which genes should be used in species tree building, gene function, evolution of gene families and study of genome evolution?
Lecture summary
