Generating Genetic Variation Flashcards
Ch. 9, Ch. 10
What are the different mechanisms of gene alteration that lead to genetic variability?
point mutations, mutations within a gene, mutations in regulatory DNA, gene duplication, exon shuffling, transposition
What is a point mutation?
Failure in the normal mechanism for copying and repairing DNA, usually 1 incorrect nucleotide. Point mutations generally have no effect on gene (part of intron), sometimes they can be detrimental
What is reverse transcriptase?
Makes DNA from RNA
What are the key steps in the HIV lifecycle?
HIV enters host cell through endocytosis, protein envelope is disassembled, reverse transcription occurs, viral DNA enters nuclear membrane and is added to DNA, when DNA is transcripted, the Viral DNA is made.
How is HIV treated?
Entry inhitibitors prevent some HIV viruses from entering cell, inhibitors for reverse transcriptase, inhibitors for integrase (puts viral DNA into real DNA), protease inhibitors slow proteins from maturing
What is a retrotransposon?
When a small piece of Dna is copied, turned into RNA, then made into DNA again through reverse transcription and inserted into a new piece of DNA. If it is inserted into introns it wont really do anything, if it is inserted into a regulator it wont survive evolution
What is a transponson?
A piece of DNA which can move around the genome, it can be bad if put into a coding section or regulator
What is the result of Mobile Element Insertions?
A copy of DNA on a neighbouring chromosome which can move around
How do intronic mobile elements lead to gene duplication and family variants?
if they have the same dna sequences before and after, they can recombine and add a second copy of the dna
How do intronic mobile elements lead to exon shuffling and generation of proteins with conserved protein domains?
The movement is facilitated by the enzyme ‘transposase’ which stitches the mobile element into new
sites on the basis of short repetitive sequences usually found at the end of the element
Define percent identity
Measure of similarity between two sequences of DNA
Define homology
existence of shared ancestry from structures or genes
