Lecture 28 Flashcards
Describe homology
Any characteristic of an organisms that is derived from a common ancestor
Describe Analogous Traits
Similarities between organisms that were not in the last common ancestor
What is used to infer homology?
Sequence similarity
A matched characteristic is usually considered….
Homologous
How are deleterious variations removed?
They are removed from the population by negative selection
What does conservation over long periods of time imply?
Strong negative selection
Which change occurs more frequently in protein sequences? Conservative or radical?
Conservative
What occurs more frequently? Synonymous base substitutions or non-synonymous?
Synonymous (no amino acid change)
Non-coding sequences evolve at a similar rate to..
Synonymous sites
Describe the evolution rate of pseudogenes
Evolve at a high rate
Which of the codon positions are less well conserved?
The third codon position
Describe how INDELs preserve the frame of the protein
Alignment will change in multiples of 3
Which variation is more commonly seen by chance and at what rate?
Non-synonymous variation is 2x more common than synonymous
How would you write a bacterial gene?
They are written with lowercase for the first letter and written in itallics
How would you write a bacterial protein?
Written with uppercase for the first letter and the rest written in normal text
What is the BLOSUM62 matrix used for?
Scoring amino acid similarity by how frequently different amino acids have replaced each other
-looking at non-synonymous
The genetic code is described as robust, what does this mean?
That point/frame-shifts are more likely to preserve chemical properties of the protein they encode
