✓ Chapter 8.3 Evidence for the Theory of Evolution: Comparative Genomics Flashcards
Define genomics
The study of the whole set of genes of a species and the interactions of the genes within a genome
Define molecular homologies
The identification of shared biomolecular elements (generally genes) used to test the closeness of relationships between organisms
Define homology
The similarity between a pair of structures, or genes in the case of molecular homology, due to shared ancestry.
Define taxon (plural taxa)
A named group of organisms e.g. beetles, reptiles.
Define clade
A group of organisms that includes all the descendant of a common ancestor and the ancestor species itself e.g. birds, dinosaurs, crocodiles
Define relatedness
A measure of evolutionary distance.
Define comparative genomics
Field of biological research in which researchers use a variety of tools to compare the genome sequence of different species
Define DNA-DNA hybridisation
A method used to analyse relatedness. Similarities in the base pairing of DNA strands are analysed to show evolutionary links between organisms.
Why is mRNA used in evolutionary studies?
Because mRNA is transcribed from DNA and reflects active genes, which helps in compare gene expression among species
Why is DNA-DNA hybridisation useful in studying evolutionary relationships?
It allows scientists to compare genetic similarities and differences by seeing how well DNA strands from different organisms bind together
What does it mean if DNA from two species hybridises well?
They have a closer evolutionary relationship due to more similar DNA sequences
What does high DNA hybridisation suggest?
A close evolutionary relationship between the species due to more similar DNA sequences
What does low DNA hybridisation suggest?
A more distant evolutionary relationship because of greater differences in DNA sequences
Why are genetic similarities important in understanding evolution?
They provide evidence of common ancestry and help map out evolutionary trees
What causes subtle differences in phenotypes between species?
Mutation in genes which results in different sequences of bases
Define bioinformatics
The digital storage. retrieval, organisation and analysis of a large volume of biological data
Define molecular phylogeny
The study of evolutionary relationships using comparative genomics
What do phylogenetic trees show?
They show how organisms are related to each other but it is hypothetical not a certain fact.
Define a node in reference to a phylogenetic tree and what does it represent
Each point where two branches split and it represents a common ancestor shared by as least two species.
Define tip in reference to a phylogenetic tree
It is found at the end of a branch where a species/taxon name is found
Define root in reference to a phylogenetic tree
The last node of the phylogenetic tree.
This is the common ancestor of all the species in the tree
Define branch in reference to a phylogenetic tree
A line drawn in the phylogenetic tree
Define clade in reference to a phylogenetic tree
A group of organisms that includes all the decedents of a common ancestor and that ancestor
Define convergent evolution and what animals are an example of convergent evolution.
A process whereby unrelated organisms evolve similar adaptations in response to a similarity in their environments
Example is legless lizards and snakes
